We measured the serum concentrations of a variety of lipid constituents – total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, apolipoproteins A1 and B, and lipoprotein(a) – in well-matched uremic patients undergoing chronic hemodialysis with either cuprophane (n = 13) or polysulfone (n = 13) membranes. We found that the patients on polysulfone membrane dialysis had significantly higher mean HDL cholesterol and apolipoprotein A1 concentrations than the patients on cuprophane membrane dialysis. There were no significant differences in the other variables studied. Moreover, polysulfone membrane dialysis was associated with a lower prevalence of potentially atherogenic lipid abnormalities such as low HDL cholesterol levels and high total cholesterol/HDL cholesterol rations. We concluded that the use of more physiological dialysis procedure may improve, in the long term, lipid and lipoprotein profiles in hemodialysis patients, though the exact mechanism(s) remains unknown.