Fasting serum cholesterol and serum triglyceride levels were determined in 15 maintenance hemodialysis (MH) and 35 renal transplant (RT) patients. Fourteen of 15 MH patients (93%) had elevated triglyceride levels (greater than 140 mg/100 ml) compared to 11 of 35 RT recipients (31%) (P less than .001). Two of 15 MH patients (13%) had elevated cholesterol levels (greater than 230 mg/100 ml), compared to 18 of 35 RT recipients (51%) (P = .03). In MH patients, a positive correlation was noted between serum triglyceride levels and carbohydrate intake (P = .03). Autopsy material from 12 children who underwent MH or RT was compared to material from 16 age-matched controls; an increased collagenous content of intima, a possible early indicator of coronary artery disease, was noted more frequently (P less than .006) in index patients compared to controls. Our data demonstrate that hyperlipidemia is a frequent finding in pediatric patients treated with MH and RT, and may be associated with premature coronary artery disease.