Thirty-one patients, mean age 54 years, had been on chronic ambulatory peritoneal dialysis (CAPD) for an average of 38 months. Mean values (mg/dl) for triglycerides (567), total-C (267), LDL-C (133), and Apo-B (154) were elevated, and HDL-C (30) were low. The low values for total-C/Apo-B and LDL-C/Apo-B suggest an increase in the number of low density lipoprotein (LDL) particles, rather than in the amount of cholesterol per LDL particle. Without knowledge of lipids, ischemic heart disease for the 31 patients was categorized into five grades in the following manner. All patients were graded based on history (angina, myocardial infarction, and bypass surgery), electrocardiogram (EKG), and echocardiography. In addition, five patients underwent coronary angiography, the results of which were considered in their grading. The five grades were assigned as follows: Grade I, no evidence (n = 15); Grade II, angina with EKG ischemia (n = 4); Grade III, myocardial infarction (MI) (n = 1); Grade IV, MI with dyskinesia-akinesia on echo (n = 4); Grade V, severe three vessel disease on angiography, or multiple infarcts, or Grade IV with heart failure (n = 7). Only Apo-B (r = 0.56) and total-C/HDL-C (r = 0.57) correlated with severity of grade, with p less than 0.001. When patients with and without detectable ischemic heart disease were compared by stepwise logistic regression, Apo-B was the only variable that independently predicted heart disease (p = 0.001). However, contribution of the lipid changes induced by CAPD has not been established.