Lipids, apoproteins and associated enzyme activities in type 2 diabetic end-stage renal disease (ESRD) were compared with that in nondiabetic ESRD and normal controls. Of the 40 uremic patients with non-insulin-dependent diabetes mellitus, 20 patients were receiving stable continuous hemodialysis treatment (CHT). Of the 39 patients with nondiabetic ESRD, 21 were undergoing CHT. Patients with nondiabetic ESRD exhibited elevated levels of serum triglyceride and a marked reduction in high-density-lipoprotein (HDL) cholesterol. Concentrations of serum apolipoprotein (Apo) C-3 were higher than in controls, whereas mean levels of serum Apo E were lower. The concentrations of serum Apo A-1 and Apo A-2 decreased with diminished lecithin: cholesterol acyltransferase activity. Lipoprotein lipase activity decreased in undialysed patients, and hepatic triglyceride lipase activity decreased significantly throughout the observation. Patients with diabetic ESRD exhibited elevated serum Apo B and normal serum Apo E levels, besides the lipid and Apo abnormalities observed in nondiabetic ESRD. Moreover, a prominent reduction in serum Apo A-1 was found in dialysed diabetic patients. The Apo B/Apo A-1 ratio was significantly higher in diabetic ESRD than in nondiabetic patients undergoing CHT. These results indicate that lipid abnormalities are accelerated in diabetic ESRD and may constitute a serious risk for the development of atherosclerosis.