The American Bulldog varies in size and type. Breeders can’t agree upon the ideal type. Be it small and compact, or larger and heavier, it is a reliable and healthy guardian dog. 
A heavy dog with light feet, the American Bulldog is a potent medium-large dog, at first sight with a large and athletic Bulldog appearance (and not Terrier). The head is described as a drawer, and the skull is large and square, not narrow or pointy. The eyes are round and well separated; the ears in rose or dropped. The body is robust and potent, not too wide, with the chest deep and the back relatively short. The neck is quite short and the shoulders broad and strongly muscled. The hindquarters, moderately angled; the forequarters, straight and well muscled. The tail should have enough length to reach the hocks, medium width and not straight or docked. The coat is short, hard and shiny. The ideal American Bulldog stands at 63 cm to the withers and weighs 60 kg. The males stand between 56 and 71 cm, and the females, between 43 and 66 cm; males weigh between 45 and 65 kg; the females, 12 kg less. As for color, at least 50% of the dog is white, with brindle patches or brown tonalities; completely white specimens are admitted. Solid black, black and tan, black and liver, merle or fawn with a black mask.
Tough and brave, the American Bulldog has become popular as a guardian dog. It is a tremendous athlete and good natured, curiously charming with children (and still a fierce protector). It needs attention and requires a firm owner, since at the beginning it tends to be square headed. Its greatest concern in life is to please its owner. The adult American Bulldog is a cheerful, sensitive dog that loves fun.
At seven weeks, males weigh some four to six kilos, females a little less. Size differences are due in part to differences between individual breeding lines. The future owner should avoid oversized specimens. The breed is naturally large and strong boned. If this is taken to excess, we are only encouraging hip dysplasia, joint malformation, stomach torsion and other related problems. The American Bulldog matures slowly, especially physically. Maturity is not reaches until over two years. Usually maximum height is reached after the first year, and the dog will finished widening at the chest on the following months. In adolescence dominance and guard instincts emerge. These should be channeled appropriately. Especially dominance should be controlled from early age, and aggression should never be tolerated.
The muscular American Bulldog can be aggressive towards other dogs, despite its good disposition. 
Due to its relative rarity, the American Bulldog does not have a broad clinical history. However, the future owner should watch hip dysplasia, joint or bone malformation, excessive lower prognathism, narrow hindquarters and other many things that affect Bull type breeds. In addition, we should watch for deafness and/or blindness, which we should suspect on completely white dogs and breeding lines that have white specimens. A firm and consistent specimen should begin early, since this is an immensely strong and dominant dog. Abundant non aggressive exercise and a rigorous training help keeping the American Bulldog happy. Care is minimal. Appetite is huge!

Puppies grow gradually but nonstop. The owner should be the “boss” from the beginning, to prevent the puppy from owning the house.