Among cat fanciers this is the most popular of all the longhaired breeds. In show cats the coat must be uniform in color, but any shade of blue is accepted. Most breeders work for the paler tone, which gives the cats a nearly lilac hue. Deeper shades, almost lavender, also occur. In non-show cats it is not uncommon for the coat to be spotted with white on the underside. For show the eyes must be orange or coppery. Yellow and green eyes occur regularly in the breed. All have a prominent neck ruff that frames the wide head. The ears are small. Some have been bred to have very short noses, so that they have an almost Pekingese appearance, but accompanying this is the feature of running or "weeping" eyes, not desirable for show purposes.

The Blue Longhair or Blue Persian is often used in breeding to maintain or to improve the standards of other longhaired cats. It is difficult, therefore, to be sure of the genetic purity of two blue parents. The litter they produce may not contain any blues at all, or occasionally a blue will appear in a litter of tabbies or other non-blue parents.