In a group of 80 patients dialyzed at the same dialysis center, dialysis arthropathy was diagnosed in ten of them. Before commencing the study all ten patients were undergoing hemodialysis with cuprophan membrane (CU). We then replaced CU with high permeability membrane (polyacrylonitrile AN 69 Hospal or polysulfone) in eight of these ten patients. Clinical and radiological evaluation as well as bêta 2 microglobulin measurement were performed at the onset of the study and at one year and two years intervals after replacing the dialysis membrane. An improvement of joint symptomatology was noted in all patients. However, the radiological abnormalities appeared unchanged or aggravated and the mean serum concentration of bêta 2 microglobulin was lower at the end of the study but not significantly.