Twenty hemodialysis (HD) patients and 20 patients on continuous ambulatory peritoneal dialysis (CAPD) were investigated for lipids, lipoproteins and apolipoproteins abnormalities. HD patients had elevated serum triglyceride, decreased high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (Apo A-I), while CAPD patients had elevated total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), Apolipoprotein B (Apo B), Apo B/Apo A-I ratio, and decreased HDL-C, Apo A-I. Because of the molecular sieving effects of peritoneum, CAPD have a negative effect on these abnormalities. CAPD patients might be at greater risk of developing coronary artery disease than HD patients who are also at increased risk as compared with normals.