There is a huge diversity of looks in the Mudi. They can have different colours (mainly black but also white, fako, brown, grey and merle) and they can also have a different size. The sizes can vary between 35 cm and 47 cm (and more). Beside this, you have Mudi's with a full tail, with a ¾ tail or a half tail. Some Mudi's are even born without tail! The tail, if they have one, is weared in calmness. When a Mudi is working, the tail has to be weared semicircular behind and above the back.

There are also many differences in coat: short, rigid hair, softer light wavy hair and explicit curly hair. Anyway you can recognise a Mudi immediately: they have a typical expressive expression. A Croatian Shepherd and a Mudi aren't always so easy to discern. A Croatian Shepherd is a bit bigger and is more stocky.

A Mudi has to have a short coat with short, smooth hair on the head and a bit longer, smooth hair on the front- and hind-leg. On the body, the hair has to be wavy or curly. The hairiness is glossy and may not become felt. The coat of a Mudi is easy to maintain. He has a long head with a pointed muzzle and barely a fuse. The ears have the shape of a V, are pointed and standing. They may not tick off. The eyes has to be oval, dark and somewhat diagonal placed. The body is streched out and good rugged so a flexible, stately, fast and maneuverable movement is possible. The height at the withers has to be between 35 and 47 cm, the weight varies between 8 and 13 kg.