The specific lipid alterations in plasma and four different tissues, as well as the activities of plasma lecithin-cholesterol acyltransferase (LCAT) and tissue lipolytic enzymes were determined in experimental nephrotic and control rats. In nephrotic rats, the cholesterol level in the heart was significantly increased, while the kidney level was decreased. When expressed per unit protein, the cholesterol level in the adrenal was also increased. The respective triglyceride and phospholipid levels were similar in both groups, except for the significant increase in the adrenal triglyceride of nephrotic rats when expressed per unit protein. The tissue lipolytic activities were significantly reduced in the heart and adrenals of the nephrotic rats. The plasma LCAT was increased, and electron-microscopically heterogenous lipoproteins (very-low density and high-density lipoproteins) were demonstrated in the nephrotic rats. These results suggest that an excess of abnormal lipoproteins in the circulation may contribute to an increased uptake of cholesterol by circulatory organs like the heart and that an accumulation of cholesterol in the circulatory organs may accelerate atherosclerosis in nephrotic syndrome.