Determinations of the plasma lipoids and of the respiratory quotient and total metabolism (Tissot method) have been performed with nephritics and normal subjects before and after they ingested fat in the proportion of 1 gm. per kilo body weight. After fat ingestion a greater increase of fatty acids and lecithin was noted in the plasma of nephritics with initially high blood lipoids than in the plasma of normal subjects or of nephritics without constant lipemia. In cholesterol no differences were found. The nephritic patients with constant lipemia were able to burn fat as efficiently as normal individuals. The accumulation of fat in their blood may be due to a disturbance in the mechanism for transferring lipoids from the blood to the tissue depots.