Hereditary nasal parakeratosis (HNPK) is inherited as a monogenic autosomal recessive skin disease in the Labrador Retriever and Greyhound. Affected dogs show scales and crusts on the nosepad. Occasionally they also develop painful fissures on the nose. We identified the causative mutations for HNPK in both breeds. Our findings enabled the development of genetic tests, which allow the unequivocal diagnosis of carrier animals.