The name of this breed is very misleading, seing how it is not a true mountain Molosser type dog, but rather a recent re-creation of the old Brabanter Bullenbeisser. The American Molosser was developed from American Bulldogs, Bandogs and German Rottweilers, although Boxers, Pit Bulls, Neos, Bullmastiffs, Cane Corsos and other breeds were used in the early days, too.

Although standardized and of loosely established type, the Bull Molosser is bred primarily for function and not just form, following the same rules used for the original working bulldogge population of Europe. Intended to be the ultimate working protection dog, this sturdy, muscular and very powerful breed is a result of a selective breeding program using only temperament-tested dogs who proved themselves in protection work trials.

The American Molosser is an intruder's worst nightmare, but this fearless breed is also a very loyal and loving family dog, as well as a capable hog hunting dog. Dog-aggressiveness is undesirable in this breed, but this is a dominant bully and early socialization is still needed. Broad-chested, muscular and strongly boned, the American Molosser is an athletic working dog, quite fast and remarkably agile. The head is broad and substantial, with a strong muzzle and powerful jaws. The ears and tail can be cropped or left unaltered.

The coat is short, flat and smooth, coming in shades of black, blue, red and brown, preferably brindled and with some white markings, but white dogs and examples whose coat is predominantly white aren't allowed. Average height is around 24 inches, although taller dogs are accepted, as long as they're athletic and functional.