Serum apolipoproteins A (Apo-A) and B (Apo-B) and lecithin: cholesterol acyl transferase (LCAT) activities and 24-hour urinary cholesterol levels were estimated in 25 nephrotic children before and during steroid treatment with 4 weeks of daily prednisolone followed by another 4 weeks of alternate-day prednisolone. The patients with untreated nephrotic syndrome (NS) showed significant decrease in serum Apo-A and LCAT activities associated with significant increase in serum Apo-B and urinary cholesterol levels compared to healthy controls (n = 25). Serum Apo-A levels correlated directly and Apo-B levels inversely with the serum albumin concentrations. After a transient elevation, the serum Apo-A level returned to control range by 8 weeks of treatment accompanied by a gradual increase in serum LCAT activity and decrease in urinary cholesterol excretion. Though, the serum Apo-B level was decreased with treatment, it was still significantly high compared to the controls.