American Mastiff

Breed Information

Mastiff Dog

United States




10 -12 years

Male: 32-36 in (81-91 cm)
Female: 28-34 in (71-86 cm)

Male: 73-91kg (160-200 pounds)
Female: 64-82kg (140-180 pounds)

Colors Are Fawn
Apricot & Brindle. White Markings Acceptable On Feet
Chest & Chin/Nose


American Mastiff dog comes in colors like beige, apricot and brindle. Puppies are born dark and tend to lighten as they age. American Mastiffs attain their true colors at the age of about one year. White markings on the chin, chest and feet are acceptable. All American Mastiffs must have a black mask in order to meet the breed standard.

The head should be wide, heavy and rectangular in shape with high-set ears rounded. A medium sized muzzle should be well proportioned with the rest of the head. The neck should be strong with a slight arch, leading to the back straight and muscular. The chest should be deep, broad and well rounded. The front legs should be strong, straight and well separated, while the hind legs should be wide and parallel. The dog should be 32 to 36 inches at the shoulder with females standing 28 to 34. American Mastiff puppies are usually dark in color, but as they mature their color tends to lighten. Common colors are fawn American Mastiff, apricot and brindle. The dog must have a temperament that is loving and devoted to his family, especially children. A loyal and calm dog, the American Mastiff should be non-aggressive, except when his family is threatened. In such cases, they become fierce and courageous guard dogs.