A mismark is a very serious color fault in the Pembroke Welsh Corgi for the show ring. A mismark is described in the standard as "Self colors with any area of white on back between the withers and the tail, on sides between elbows and back of hindquarters, or on ears. Black with white markings and no tan present." There should be no white above an imaginary horizontal line drawn from the elbow through the stifle joint. White should not extend far into the upper arm and shoulder blade areas, nor should it appear on the thigh as other than a narrow stifle trim. Some red or tan, however pale, must appear on a white-marked black dog. Mismarks should not be bred. No different in personality from a Corgi with proper markings, they make excellent pets.

This depicts a Pembroke Welsh Corgi with the desirable maximum amount of white markings.

This depicts a Pembroke Welsh Corgi with heavy but acceptable white markings.