Custom Search
Dog Breed Info Center Facebook Page DogBreedInfo Youtube Page Pintrest Button



American Mastiff

Information and Pictures

Duke a good example of an 18-month-old male American Mastiff with a fawn coat.


Other Names

AM Mastiff


uh-MAIR-ih-kuhn MAS-tif


The American Mastiff has a much drier mouth than other Mastiffs. The drier mouth is due to outcrossing the English Mastiff with Anatolian Mastiff, which occurred early in the development of the breed. The American Mastiff is a large, massive and powerful dog. The head is wide, heavy and rectangular in shape. The eyes are amber in color, the darker the better. The ears are rounded and set high on the head. The muzzle is medium sized, and well-proportioned to the head, which has black mask. The nose is black. It has a scissor bite. The neck is powerful and slightly arched. The chest is deep, broad and well-rounded, descending to the level of elbows. The ribs are well-sprung and extend well back. The back is straight, muscular and powerful, with well-muscled and slightly arched loins. The forelegs are strong, straight and set well apart. The hind legs are wide and parallel. The feet are large, well-shaped and compact with arched toes .The tail is long, reaching the hocks. Puppies are usually born dark and lighten as they grow older, some becoming very light fawn by age one; some retain dark hairs. Colors are fawn, apricot and brindle. White markings acceptable on feet, chest and chin/nose. Temperament: Dignity rather than gaiety; quiet, calm, loving and loyal. Protective, but not aggressive.


The American Mastiff loves children and is totally devoted to its family. It is non-aggressive except in those instances when its family, especially the children, are threatened. In those instances it becomes a courageous defender. The American Mastiff is wise, kind and gentle, patient and understanding, very loving with its own people, neither shy nor vicious. It is loyal and devoted. Since these dogs are of the Mastiff type and grow to be very large, this breed should only be with an owner who knows how to display strong leadership.The objective in training this dog is to achieve pack leader status. It is a natural instinct for a dog to have an order in its pack. When we humans live with dogs we become their pack. The entire pack cooperates under a single leader; lines are clearly defined and rules are set. You and all other humans MUST be higher up in the order than the dog. That is the only way your relationship can be a success.

Height, Weight

Height: 28 - 36 inches (65 - 91 cm)

Weight: Males 160 to over 200 pounds (72 - 90 kg) Females 140 - 180 pounds (63 - 81 kg)

Health Problems

American Mastiffs tend to be healthy, happy dogs with fewer reported incidents of many of the health problems you see in other large breeds.

Living Conditions

American Mastiffs do just fine in an apartment with daily exercise; a walk will do, or a run in a fenced-in yard. As they grow older they tend to become a little lazy. They are relatively inactive indoors ("couch potatoes") and a small yard will do.


Mastiffs are inclined to be lazy but they will keep fitter and happier if given regular exercise. Like all dogs, the American Mastiff should be taken on daily regular walks to help release its mental and physical energy. It's in a dog’s nature to walk. They should always be leashed in public.

Life Expectancy

About 10-12 years


The smooth, shorthaired coat is easy to groom. Brush with a firm bristle brush and wipe over with a piece of toweling or chamois for a gleaming finish. Bathe or dry shampoo when necessary. This breed is an average shedder.


Developed by Fredericka Wagner of Piketon, OH, at Flying W Farms by crossing the English Mastiff with an Anatolian Mastiff. The resulting puppies had a firmer, tighter lower lip line and did not drool as much as the average Mastiff; selective breeding thereafter kept the drier mouth.




AMBC = American Mastiff Breeders Council

BBC = Backwoods Bulldog Club

CKC = Continental Kennel Club

DRA = Dog Registry of America, Inc.

"Max" and three year old American Mastiff, male, brindle coat

Max, a three-year-old American Mastiff, male, brindle coat



"Gideon, a three year old American Mastiff, male, fawn coat

Gideon, a three-year-old American Mastiff, male, fawn coat

"Gideon, a three year old American Mastiff, male, fawn coat

Gideon, a three-year-old American Mastiff, male, fawn coat



American Mastiffs

Bart at 11 months, owners: The Robinette Family—"This is Bart, an eleven-month-old American Mastiff, apricot color. Bart has the typical short, smooth American Mastiff coat."Photo courtesy of American Mastiff (Flying W)



American Mastiff Puppy Dogs

"Jake Jr. is only three months old and is very, very light fawn with very exceptional mask. Jake has the very short, smooth American Mastiff coat." Photo courtesy of American Mastiff (Flying W)



American Mastiff Puppy Dogs

"Grande is an 8-week-old puppy in this photo and is a very, very rare "fluffy" (longer coat). Fluffies are seldom seen in the American Mastiff but they do exist. Grande is a lovely fawn/apricot." Photo Courtesy of American Mastiff (Flying W)