Twenty-five patients had their lipid profile monitored sequentially for up to 3 years post-transplant. All patients had good graft function throughout the study. Forty-four percent remained hypertriglyceridemic. The lipid level was not due to diet or excessive weight gain. Triglyceride turnover studies showed that overproduction was the predominant defect in patients receiving massive steroids to reverse rejection and in stable long-term recipients. Repeat metabolic investigations in the latter group, after changing to alternate-day, equal-dose steroid therapy showed improvement in both the absolute triglyceride concentration and the triglyceride production rate. The correlation observed between basal insulin level and triglyceride concentration suggests the drug may act through this hormone, stimulating hepatic triglyceride production. A change to alternate-day steroid therapy should be considered in post-transplant patients who are hyperlipemic while receiving minimal daily prednisone therapy.