Mastiff and Rottweiler Mix Puppies: The Mastweiler Breed Guide
Everything about mastiff and rottweiler mix puppies — size, temperament, health risks, cost, and whether this giant designer cross suits your household.
If you've searched for mastiff and rottweiler mix puppies, you've likely encountered the name "Mastweiler" — a designer cross between two of the most powerful guardian breeds in the world. This is not a casual pet choice. A fully grown Mastweiler can weigh over 150 pounds, carry serious protective instincts from both parent lines, and demand an owner who understands large-breed handling, early socialization, and joint-health management from puppyhood onward.
This guide breaks down what you can realistically expect from a Mastiff × Rottweiler cross — including the traits that are fairly predictable, the ones that vary wildly between individual puppies, and the health screenings any responsible breeder should provide before you bring a puppy home.
Parent Breed Breakdown: Mastiff Meets Rottweiler
Understanding a mixed-breed dog starts with understanding each parent. The English Mastiff and the Rottweiler share some traits (loyalty, guarding instinct, large size) but differ significantly in energy level, trainability, and social behavior.
| Trait | English Mastiff | Rottweiler |
|---|---|---|
| AKC Weight Range | 120–230 lb (54–104 kg) | 80–135 lb (36–61 kg) |
| AKC Height Range | 27.5–30+ in (70–76+ cm) | 22–27 in (56–69 cm) |
| Lifespan | 6–10 years | 9–10 years |
| AKC Group | Working | Working |
| Energy Level | Low — short walks, lots of lounging | Moderate-High — needs daily vigorous exercise |
| Trainability | Moderate — can be stubborn, responds to patience | High — eager to work, excels in obedience |
| Guarding Instinct | Strong — territorial, reserved with strangers | Very Strong — confident guardian, aloof with strangers |
| Shedding | Moderate — short coat, seasonal blow | Moderate — short double coat, seasonal shedding |
| Drooling | Heavy — brachycephalic-influenced loose lips | Moderate |
| Common Health Issues | Hip/elbow dysplasia, gastric dilatation-volvulus (bloat), heart disease, cystinuria | Hip/elbow dysplasia, aortic stenosis, osteosarcoma, degenerative myelopathy |
Sources: AKC Mastiff Breed Standard, AKC Rottweiler Breed Standard.
What Two Breeds Make Up the Mastweiler?
The Mastweiler is a first-generation or multigenerational cross between the English Mastiff and the Rottweiler. Some breeders may use the Bullmastiff (itself a Mastiff × Bulldog cross) instead of the English Mastiff, which produces a slightly smaller, more athletic dog. Always ask the breeder which specific Mastiff-type breed was used.
Understanding Generation Labels
- F1: One purebred English Mastiff parent × one purebred Rottweiler parent. Maximum genetic diversity, but trait predictability is lowest — puppies in the same litter can look and behave very differently.
- F1B: An F1 Mastweiler bred back to one of the parent breeds (usually the Rottweiler for slightly smaller size or the Mastiff for more laid-back temperament). Introduces some predictability but reduces hybrid diversity.
- F2: Two F1 Mastweilers bred together. Trait expression becomes more variable again as recessive genes recombine.
- Multigen (F3+): Multiple generations of Mastweiler-to-Mastweiler breeding. Theoretically more predictable, but this cross is rare enough that established multigen lines are uncommon as of 2026.
Most Mastweilers available are F1 crosses. The designer market for this particular mix is small compared to doodle breeds, so established multigen programs are difficult to find.
How Big Will a Mastiff and Rottweiler Mix Get?
This is one of the most common questions prospective owners ask, and the honest answer is: the range is wide. Because both parent breeds are large but differ by 50+ pounds at the upper end, individual puppies can land anywhere across that spectrum.
| Category | Weight Range | Height at Shoulder |
|---|---|---|
| Male F1 (typical) | 115–180 lb (52–82 kg) | 25–30 in (64–76 cm) |
| Female F1 (typical) | 90–145 lb (41–66 kg) | 24–28 in (61–71 cm) |
| F1B back to Mastiff | 130–200+ lb (59–91+ kg) | 26–31 in (66–79 cm) |
| F1B back to Rottweiler | 85–140 lb (39–64 kg) | 23–27 in (58–69 cm) |
Growth timeline: Like most giant breeds, Mastweilers grow slowly. Expect them to reach roughly 70% of adult weight by 6 months, but they won't fully mature in bone density and muscle mass until 18–24 months. Overfeeding puppies to "bulk them up" accelerates growth and increases hip dysplasia risk — feed a large-breed puppy formula (AAFCO-certified) and follow your vet's body condition scoring, not the bag's suggested amount.
Temperament: What to Expect (and What's Unpredictable)
Temperament is where mixed-breed dogs are most variable, and a Mastiff × Rottweiler cross is no exception. Even littermates can diverge significantly.
Temperament Spectrum in Mastweilers
| Trait | Leaning Mastiff | Leaning Rottweiler | Most Common Middle Ground |
|---|---|---|---|
| Energy | Low — prefers 20–30 min walks | High — needs 60+ min vigorous activity | Moderate — 45 min daily exercise |
| Stranger Reaction | Indifferent, may ignore visitors | Alert, watchful, may block entry | Alert but accepting after introduction |
| Trainability | Slow to respond, needs repetition | Quick learner, enjoys structured work | Moderately trainable with positive methods |
| Family Bonding | Deeply loyal, velcro-like attachment | Loyal, confident, bonds strongly with handler | Strong family attachment, follows owners room-to-room |
| Child Tolerance | Generally patient, gentle giant tendency | Good with known children, may herd or body-block | Good with socialized children; always supervise due to size |
| Same-Sex Dog Tolerance | Variable — some Mastiffs are dog-selective | Can be same-sex aggressive, especially males | Early socialization critical; same-sex households risky |
| Barking | Low — tends to be quiet unless provoked | Moderate — will alert-bark at triggers | Low-to-moderate, alert barking |
Best-case scenario: A confident, calm dog that is gentle with family, accepting of visitors once introduced, responsive to training, and content with moderate daily exercise.
Challenging scenario: A large, powerful dog that inherits the Rottweiler's guarding intensity combined with the Mastiff's stubbornness — resistant to training, reactive to strangers, and difficult to physically manage at 150+ pounds. This is why early socialization and professional positive-reinforcement training are non-negotiable for this cross.
Training note: Force-free, positive reinforcement methods (treat-based rewards, clicker training, counter-conditioning for stranger reactivity) are the only recommended approach for guardian breeds. Aversive tools like shock collars or prong collars can escalate aggression in powerful dogs and damage the trust bond. Work with a certified professional dog trainer (CPDT-KA or IAABC-credentialed) who has guardian breed experience.
Coat, Shedding, and Grooming Needs
Is this mix hypoallergenic or low-shedding? No. Neither parent breed carries the low-shedding, hair (rather than fur) coat gene found in Poodles. A Mastweiler will have a short, dense double coat and will shed moderately year-round with heavier seasonal shedding in spring and fall.
Coat Possibilities
- Mastiff-dominant coat: Very short, fine, single-layer — moderate shedding, easy to brush
- Rottweiler-dominant coat: Short but denser double coat with a defined undercoat — heavier seasonal blow
- Color: Almost always some combination of black, tan/mahogany markings (Rottweiler influence), fawn, apricot, or brindle (Mastiff influence). The classic black-and-tan Rottweiler pattern is common but not guaranteed.
Grooming Schedule
| Task | Frequency | Recommended Tools |
|---|---|---|
| Brushing | 2–3× per week (daily during shedding season) | Rubber curry brush or medium-bristle brush; undercoat rake during blow |
| Bathing | Every 6–8 weeks or as needed | Oatmeal-based canine shampoo; avoid human products |
| Nail trimming | Every 3–4 weeks | Heavy-duty guillotine or scissor clippers; grinder for thick nails |
| Ear cleaning | Weekly check, clean as needed | Veterinary ear wash; floppy Mastiff-type ears need more attention |
| Dental care | Daily brushing ideal, minimum 3× per week | Canine enzymatic toothpaste, finger brush or large-breed toothbrush |
| Wrinkle care (if Mastiff-dominant face) | Daily if facial folds are present | Wrinkle wipes or damp cloth; dry thoroughly to prevent yeast infection |
Health Considerations: Hybrid Vigor Myth vs. Reality
Let's address a persistent myth: "hybrid vigor" does not eliminate health risks in designer crosses. The concept of heterosis (hybrid vigor) is real in population genetics, but it primarily benefits traits controlled by many genes (like overall vitality). It does not protect against inherited conditions that both parent breeds share — and the Mastiff and Rottweiler share several serious ones.
According to data compiled in the Merck Veterinary Manual and breed-specific health registries, here are the conditions a Mastweiler may inherit from one or both parent breeds:
| Condition | Parent Source | Prevalence | Screening Test | Estimated Treatment Cost (USD) |
|---|---|---|---|---|
| Hip Dysplasia | Both | Mastiffs: ~13%; Rottweilers: ~20% (OFA data) | OFA/PennHIP radiograph at 24 months | $1,500–$7,000 (surgical) |
| Elbow Dysplasia | Both | Rottweilers: ~11%; Mastiffs: ~6% | OFA elbow radiograph | $1,500–$4,500 (surgical) |
| Gastric Dilatation-Volvulus (Bloat) | Both (deep-chested breeds) | Lifetime risk in giant breeds: 5–25% | No genetic test; preventive gastropexy available | $1,500–$7,500 (emergency surgery) |
| Aortic Stenosis | Rottweiler (primary) | ~5–10% in Rottweilers | Cardiac auscultation + echocardiogram | $500–$3,000 (management); higher for intervention |
| Osteosarcoma | Rottweiler (primary) | Rottweilers: ~12.5× general population risk | No screening; monitor for limb lameness | $5,000–$15,000+ (amputation + chemo) |
| Degenerative Myelopathy (DM) | Both (carrier frequency varies) | Carrier rate varies by line | DNA test (SOD1 gene mutation) | No cure; supportive care $200–$500/month |
| Cystinuria | Mastiff (primary) | ~4–6% in English Mastiffs | Urine nitroprusside test or DNA panel | $300–$2,000+ (stones, surgery) |
| Cherry Eye / Entropion | Mastiff (primary) | Common in Mastiff-type breeds | Veterinary ophthalmologic exam | $300–$1,500 (surgical correction) |
What responsible breeders do: Both parent dogs should have OFA (Orthopedic Foundation for Animals) hip and elbow certifications, a cardiac clearance from a veterinary cardiologist, and DNA testing for DM and cystinuria. Ask to see certificates — not just verbal assurances. The AVMA recommends health screening for all breeding dogs, and this is especially critical for giant-breed crosses where orthopedic issues carry high treatment costs and welfare impact.
Lifespan expectation: 7–10 years. This is typical for giant breeds. Budget for higher veterinary costs in the second half of life, particularly orthopedic and oncology care.
Bloat Emergency — Know the Signs
Both Mastiffs and Rottweilers are high-risk for gastric dilatation-volvulus (GDV), and a Mastweiler inherits that deep-chested conformation. Call your emergency vet immediately if you see:
- Distended, hard abdomen
- Unproductive retching (trying to vomit but nothing comes up)
- Excessive drooling with signs of distress
- Rapid breathing or collapse
GDV is fatal within hours without surgery. Discuss prophylactic gastropexy (stomach tacking) with your veterinarian at the time of spay/neuter — this procedure reduces the risk of torsion by over 80%.
Cost: Mastiff and Rottweiler Mix Puppy Prices in 2026
The Mastweiler is not as commercially popular as doodle crosses, which affects both price and availability. Here's what the market looks like as of 2026:
| Source | Price Range (USD) | Notes |
|---|---|---|
| Responsible breeder (health-tested parents) | $1,200–$3,000 | Should provide OFA certs, health guarantee, take-back clause |
| Casual/backyard breeder | $500–$1,200 | Typically no health testing; higher risk of inherited conditions |
| Breed-specific rescue | $200–$600 (adoption fee) | Check Rottweiler and Mastiff rescues; mixed-breed adults sometimes available |
| General shelter | $50–$400 | Rare but possible; temperament evaluation important for guardian-breed mixes |
First-Year Budget Estimate
- Puppy purchase: $1,200–$3,000
- Initial veterinary (vaccines, spay/neuter, microchip): $600–$1,200
- Large-breed puppy food (12 months): $800–$1,500 (these dogs eat 5–8 cups/day at maturity)
- Gear (XXL crate, heavy-duty leash, harness): $300–$600
- Training (group + private sessions): $400–$1,200
- Pet insurance (recommended for giant breeds): $600–$1,200/year
- Total estimated first year: $3,900–$8,700
Insurance tip: For a giant-breed cross with high orthopedic and oncology risk, a comprehensive pet insurance policy with no annual payout cap (e.g., Trupanion or Healthy Paws unlimited plans) is strongly recommended. Enroll before 12 weeks of age to avoid pre-existing condition exclusions on developing joints.
Who Should (and Shouldn't) Own a Mastweiler?
This cross is not a fit for every household. Here's a practical decision framework:
| Factor | Good Fit | Poor Fit |
|---|---|---|
| Experience level | Experienced dog owner; prior guardian breed handling | First-time dog owner |
| Living space | House with fenced yard (minimum 6-foot fence for Rottweiler-influenced athleticism) | Small apartment; no outdoor access |
| Physical ability | Able to manage a 100–180 lb dog on leash; strength to control pulling | Limited mobility or physical strength |
| Household composition | Adults or families with older children (10+); dog-experienced teens | Homes with toddlers (knock-over risk); frequent unvetted visitors |
| Time commitment | Home often; can provide 45–60 min daily exercise + training sessions | Long work hours; dog left alone 8+ hours regularly |
| Other pets | Opposite-sex dog household; cats if raised together from puppyhood | Same-sex large dog; small dogs (prey drive risk from Rottweiler line) |
| Local regulations | No breed-specific legislation (BSL) in your area | BSL jurisdictions — Rottweilers are restricted in some US municipalities and many rental properties |
BSL note: Some cities, counties, and military housing authorities restrict or ban Rottweilers and Rottweiler mixes. Check your local ordinances, homeowner's insurance policy, and rental lease before committing to this cross. Laws vary significantly by jurisdiction.
Frequently Asked Questions
What two breeds make up a Mastweiler?
The English Mastiff and the Rottweiler. Occasionally, a Bullmastiff is substituted for the English Mastiff, which produces a slightly smaller, more athletic dog. Always confirm with the breeder which specific Mastiff-type breed was used.
How big will mastiff and rottweiler mix puppies get?
Adult males typically reach 115–180 lb (52–82 kg) and 25–30 inches at the shoulder. Females are generally 90–145 lb (41–66 kg) and 24–28 inches. F1B crosses back to the Mastiff parent can exceed 200 lb. Full maturity takes 18–24 months.
Is a Mastweiler hypoallergenic?
No. Neither parent breed carries the low-shedding gene. Expect moderate year-round shedding with heavier seasonal coat blows. This cross is not suitable for allergy-sensitive households.
Are mastiff and rottweiler mix puppies good with children?
They can be excellent with children they're raised alongside, but their sheer size creates a knock-over risk for toddlers. Supervision is essential. Early socialization with children of various ages during the critical 8–16 week window is important. Never leave any large dog unsupervised with young children.
How much exercise does a Mastweiler need?
Typically 45–60 minutes of daily exercise, split into two sessions. Avoid high-impact exercise (running on hard surfaces, jumping) until growth plates close at 18–24 months — consult your veterinarian for breed-appropriate puppy exercise guidelines. Swimming and controlled leash walks are ideal for developing joints.
What health issues might this mix inherit?
The primary concerns shared by both parent breeds are hip dysplasia, elbow dysplasia, and gastric dilatation-volvulus (bloat). Rottweiler-line risks include osteosarcoma and aortic stenosis. Mastiff-line risks include cystinuria and eye conditions. Demand OFA health clearances from any breeder before purchasing.
How much does a Mastweiler cost?
From a responsible breeder with health-tested parents: $1,200–$3,000. Adoption from breed-specific rescues: $200–$600. Factor in $3,900–$8,700 for total first-year costs including food, veterinary care, training, and insurance.
Can I find Mastweiler puppies in rescues?
It's uncommon but possible. Check Rottweiler-specific rescues (e.g., RottNet, Rottweiler Rescue) and Mastiff rescues (e.g., Mastiff Club of America rescue network). Adult mixes appear more frequently than puppies. Be prepared for a temperament evaluation process — reputable rescues will assess guardian-breed mixes carefully before placement.
Disclaimer: This article is for informational purposes only and does not replace professional veterinary advice. Always consult your veterinarian for health, nutrition, and behavioral guidance specific to your dog. If you suspect your dog has ingested a toxic substance, contact the ASPCA Animal Poison Control Center at (888) 426-4435 (24/7, consultation fee applies).
Beth Carrasco
All our authors care for dogs every day — read more of their work on the authors page.
