Changes in lipid concentration in fat body at various developmental stages of the cabbage worm, Pieris rapae were measured using thin layer chromatographic (Mangold, 1961) and Marzo (1971) methods, respectively. Healthy animals were chosen as samples of each developmental stage: the final instar larvae, newly molted pupae, pupae in second day, 4th, 6th, 8th, 10th day after pupation and newly emerged adults. Phospholipid, triacylglycerol, ester cholesterol, and mono-and diacylglycerol were indentified at each stages, But mono-and diacylgolycerol were present at trace. Lipid concentration in the fat body was mainly triacylglycerol fraction. Phospholipid and triacylglycerol concentrations during the 6th day pupae reached the maximum. Hence, changes in concentration of phospholipid, triacylglycerol, and ester cholesterol exhibitied a general pattern of U-shaped curve according to histolysis of larval organs and histogenesis of adult organs through the progress of life cycle.