The Weimaraner is commonly noted for its mousey or silver gray color. However, there is another variation of the Weimaraner called the Blue Weimaraner, which has a dark blue coat with a slate-gray shade. The usual gray color of the Weimaraner is a dilution of brown, but the Blue Weimaraner shows a dilution of black. Other than the color, the Blue Weimaraner is similar to the Gray Weimaraner in all aspects of the breed. This color deviation is thought to be an alteration of the breed's genetics because it has only appeared in two non-hereditary instances during the last the century.

The first instance was in Austria during the 1940s and the second time was in a Weimaraner called Caesar Von Gaiberg back in 1947. It was Captain Holt who purchased Cäsar Von Gaiberg during one of his journeys through Germany and he brought the Blue Weimaraner back to America. Caesar Von Gaiberg went on to produce fine lines of Weimaraner puppies, becoming the forefather of the Blue Weimaraner breed in America. In fact, eight of the Blue Weimaraners were recognized as bench champions.

Back in the 1940s, the Blue Weimaraner was thought to be a recessive gene. However, recent study shows that it is in fact a dominant gene. A Weimaraner has only two color alleles and in order to make a Blue Weimaraner, at least one allele should be blue. If a Weimaraner has inherited a blue allele, then it will be blue. A Gray Weimaraner from a Blue Weimaraner parent means that it did not inherit any blue allele.

The Blue Weimaraner is accepted by a number of kennel clubs and associations, but it is considered a fault by the American Kennel Club or AKC. Generally, it is not recognized by most of the major dog registries around the world. However, a Blue Weimaraner can be registered with the AKC if both of its parents are also registered with the club. Thus, an AKC-registered Blue Weimaraner may compete in any event hosted by the AKC but it will not be eligible for a show or conformation event. It was in 1972 that the standards were changed to disqualify the Blue Weimaraner. However, it is permitted to join competitions such as Obedience, Tracking, Agility, and other performance events.

Although the Blue Weimaraner is not recognized as a pure-bred Weimaraner, there are a lot of breeders who prefer to breed this type of Weimaraner. One of their missions is to get the AKC to revise the standards so that the Blue Weimaraner will be recognized. Through the efforts of the breeders, perhaps one day, the Blue Weimaraner will make a return to the show ring.