Changes in fatty substance of hot pepper fruit during the after-ripening period were studied for both neutral and polar fatty substance. The results obtained from these studies are tabulated as follows; 1. Total fatty substance decreased as the after-ripening proceeded, while neutral fatty substance was least during the climacteric period. Polar fatty substance showed sudden drop in the amount during the post-climacteric period. 2. Fatty acid composition in neutral fatty substance showed that there is decrease in linoleic acid during the post-climacteric period, and in myristic acid and oleic acid respectively during the climacteric period. Stearic acid contents also drops sharply as after-ripening proceeds. 3. Value for saturates to unsaturates in and the amount of neutral fatty substance became least during the climacteric period, indicating that there is relationship between metabolism of neutral fats and climacteric rise. 4. Fatty acid composition of polar fatty substance showed that there is decrease in linoleic acid when after-ripening takes place whereas linolenic acid increases. These became reverse in the amounts after the climacteric period, suggesting that these changes may be useful to indicate true maturity of the fruits.