Slipped capital femoral epiphysis is a well-described phenomenon in humans, characterized by an atraumatic separation of the femoral head from the femoral neck at the capital physis. The syndrome most commonly affects overweight to obese adolescent males. A similar syndrome has been described in cats, pigs, and dogs. In all species, the histopathologic lesions are similar, consisting of irregular clusters of chondrocytes surrounded by abundant chondroid matrix on either side of an unusually wide physis. This lesion in cats has been called physeal dysplasia. The etiology is idiopathic, but is believed to be multifactorial, with genetic, nutritional, endocrine, and other mechanisms involved in the pathogenesis. Slipped capital femoral epiphysis is a recently described entity in veterinary medicine, and should be included in the differential diagnosis for a young cat or dog with an acute or insidious onset of unilateral or bilateral hip lameness or pain with no history of trauma.