A study of three femoral heads removed from patients suffering from articular chondrocalcinosis enabled the authors to identify the lesions of the cartilage in that disorder. They are mainly represented by crystals of calcium pyrophosphate. They appear within the cartilage which is macroscopically intact and histologically normal, but their location and the related tissue phenomena in their formation remain controversial and poorly understood. They accumulate in the various layers of the non-calcified cartilage within which they appear to hollow out genuine cavities by pushing back and then destroying the intercellular matrix and surrounding chondrocytes. In spite of their at times considerable size, the accumulations of crystals are not accompanied with fissures or erosion of cartilage tissue. This good histological tolerance appears to be explained by the distribution of calcification outside of the areas bearing pressure, which is in agreement with the often asymptomatic nature of chondrocalcinosis. These calcfications appear to be able to render cartilage fragile and to lead to pseudoarthrosic arthropathy when they are abundant and spread through the entire surface of a joint.