The blood lipids profile was determined in 59 patients with successful primary renal allografts, who were followed for an average period of 31.8 mo. (6-80 mo.). Elevated levels of cholesterol (greater than 250 mg/100 ml) were found in 51% of the patients, elevated levels of triglycerides in 56% and elevated levels of phospholipids in all but one of the patients who were studied (45 of 46). Correlation analysis revealed significant relationships among the systolic blood pressure with total cholesterol (r [correlation coefficient] = 0.36, P < 0.01), triglycerides (r = 0.56 P < 0.001) and phospholipids (r = 0.40, P < 0.001). No significant correlations were found between the lipid levels and daily prednisone dosage or with the duration of the period following transplantation. The most significant finding was an elevation of serum phospholipid level, a pattern unreported previously in transplant recipients but which has been reported to be associated with hepatic derangement in nontransplant population. Of 32 patients who had elevated levels of serum phospholipids, the liver function tests were abnormal in 22 patients (69%).