Rice bran is the most important by-product obtained during the rice milling process. The chemical composition of rice bran varies widely that is related to the milling system and management (Ravindran and Blair, 1991). Therefore, the terminology concerning rice bran is not consistent due to the lack of well-based definitions. Rice bran contains a considerable amount of crude protein and fat which, in many countries, is now being extracted to obtain a high quality of oil. The high fat in rice bran may create rancidity problems during storage in tropical climates. The bran also contains a lipolytic enzyme that becomes active when it is separated from the rice and rapidly increase the free fatty acid content but, the storage life of solvent-extracted bran is considerably longer than the un-extracted one (Warren and Farrel, 1990). In Iran, annually about 200000 tons of this by-product is available which is used as an animal feed without any extraction process. This study was conducted to study the chemical composition and fatty acids profile of the oil fraction in rice bran during the different seasons.