Keratinization defects in dogs and cats are characterized by abnormal haircoats with concurrent scaling and crusting. In this cases series, 3 dogs with similar skin biopsy findings were described. Although the dogs were first examined as adults, signs first appeared when they were puppies. The haircoat was reported to be dry, dull, and brittle with progressive scaling, hair casts, and hair loss. Two of 3 dogs for which follow-up was available responded to topical shampoo therapy combined with topical emollients (propylene glycol spray). One dog was treated with concurrent oral vitamin A and another with evening primrose oil.