The lipid metabolism of 93 patients with renal transplantation was prospectively studied. It was characterized by the serum levels of cholesterol, HDL, LDL, triglyceride, apolipoprotein Al, Apo B and lipoprotein (a) as well as by lipid electrophoresis. In addition to the examination of lipid concentrations, the authors looked for correlations with other metabolic changes, immunosuppressive treatment and the changes of body weight and hypertension following transplantation. Their conclusion is that hyperlipidaemic and dyslipidaemic changes, as reflected by the levels of total cholesterol, LDL and Apo B, are more considerable in women than in men. The levels of pre-beta and beta lipoprotein were not significantly lower in men than in women. With the passing of time after transplantation and with the reduction of the doses of cyclosporine and corticosteroids, the values of hypertension, hyperlipidaemia and dyslipidaemia decreased. According to the follow-up results, the lipid values measured in the winter and autumn months are higher than those found in the summer. The importance of early and follow-up examinations and of the reduction of pathological metabolic alterations is emphasized.