ABSTRACT. Fasting concentrations of cholesterol and triglycerides were determined in total serum and in serum fractions of very low (VLDL), low (LDL) and high (HDL) density lipoproteins in 141 patients with chronic renal failure (CRF) of different etiologies. They were grouped according to sex and degree of renal failure. The characteristic dyslipoproteinemia of uremia, viz. hypertriglyceridemia, raised VLDL and low HDL, cholesterol enrichment of VLDL and triglyceride enrichment of LDL, was present already in the mildest, asymptomatic group (creatinine 140–400 μmol/l), highly significant for men (n=28) but not statistically significant for women (n=7). There was a negative correlation between creatinine and LDL cholesterol concentrations and between creatinine and the cholesterol/triglyceride ratio in LDL in males, otherwise the degree of renal insufficiency did not influence the dyslipoproteinemia. Neither different etiologies of CRF, nor treatment with β‐adrenergic blocking agents or thiazides did seem to influence lipoprotein levels orderly. Males on antacids had lower serum and LDL cholesterol levels, which is probably explained by the negative relation between LDL cholesterol and creatinine, as antacids are more often administered in advanced uremia. Males treated with protein‐poor diet differed from other groups by not having elevated VLDL triglycerides. It is concluded that the lipoprotein abnormalities found in uremia are present already at an early stage of renal impairment and, except for LDL cholesterol in males, fairly uninfluenced by the degree of renal function and etiology of the disease. It is suggested that the dyslipoproteinemia of CRF is caused by effects on several mechanisms in lipoprotein metabolism, e.g. deficiency of different apolipoproteins.