The thickness of the calcified zone of the articular cartilage and the number of tidemarks at the junction between articular cartilage and bone has been determined in specimens from 41 femoral heads and 42 humeral heads from cadavers aged between 25 and 93. The thickness of the calcified zone decreased with age but the number of tidemarks increased, particularly over the age of 60. These observations suggest that remodelling of the bone ends occurs and that this process is accelerated with increasing age.