The massive Mastiff is heavy-boned with a powerful musculature, being slightly longer than tall. It combines great strength with endurance. Its power and strength are evident in its gait, which should have good reach and drive. Its double coat consists of a dense undercoat and a straight, coarse, outer coat of moderately short length. Its expression is alert but kindly. The overall impression should be one of grandeur and dignity.

The mastiff is innately good-natured, calm, easygoing and surprisingly gentle. It is a well-mannered house pet, but it needs sufficient room to stretch out. This is an extremely loyal breed, and though not excessively demonstrative, it is devoted to its family and good with children.