In a retrospective study, 47 fractures of the femoral neck and 17 capital epiphyseal separations were recorded in a total of 62 animals over a 12-year period. It was found that cats sustain femoral neck fractures more often than capital epiphyseal separations. Until cats are six months old the vast majority of lesions in the proximal femur are fractures of the neck. Between the ages of six and 12 months both lesions are equally represented. After 12 months of age no capital epiphyseal separations occur and the incidence of femoral neck fractures diminishes appreciably. If left untreated, an acceptable clinical result can be obtained in both femoral neck fractures and capital epiphyseal separations, although the best functional result is achieved in femoral neck fractures. In the present study, spontaneous healing was seen only in femoral neck fractures in cats younger than three months. All cats with capital epiphyseal separations developed hypertrophic pseudoarthrosis.