The distribution of chondroitin sulphate and keratan sulphate in osteoarthritic cartilage is analysed in a histochemical study, using Safranin O, Alcian Blue‐CEC and Toluidin Blue O at different pH values. The material consisted of six femoral heads obtained during replacement surgery from patients with osteoarthritis and six control femoral heads from patients who were operated on because of either fracture or tumour. The heterogeneous distribution of glycosaminoglycans in the matrix of cartilage from the osteoarthritic and control patients is described. In addition to the depletion of glycosaminoglycans, which first was seen at the surface, osteoarthritic cartilage was characterized by increasing territorial staining of chondroitin sulphate, especially around the cell clusters. This was a constant finding, even in cartilage with only slight osteoarthritic changes. In the control patients, this phenomenon was found only in the weightbearing area in very old cartilage, or in cartilage with morphological signs of osteoarthritis. Finally, the cartilage of osteophytes contained practically only chondroitin sulphate. These histochemical findings are in accordance with the increase in the rate of35SO4incorporation despite the loss of glycosaminoglycans in osteoarthritis, as described by others, and they reflect probably an accelerated synthesis of glycosaminoglycan