A study was carried out to determine the chemical composition of rubber seed cake and to evaluate its nutritional value. Five adult bullocks were selected and each of them was fed 3 Kg of rubber seed cake to meet their protein requirement and ragi straw, fed ad lib. The study was carried out for a period of 28 days and during the last seven days a metabolism trial was carried out. From the chemical composition it is clear that there is scope for using rubber seed cake as a protein component of the diet. Effective processing can reduce the level of HCN concentration in the cake, there by rendering it safe for feeding animals. The animals did not record any loss in weight. They ingested about 3 Kg of rubber seed cake/day/animal and the dry matter intake was 1.56Kg/100Kg body weight. The average digestibility coefficients of the nutrients and the nutritive value of rubber seed cake are also presented. The study indicated that rubber seed cake can replace coconut cake, linseed cake or cotton seed cake in the ration of dairy animals. Oil was extracted from the seed of rubber (Hevea brasiliensis) and then purified. After purification its different physical and chemcial constants were determined. Higher fatty acids were identified by Urea-inclusion method and by thin layer chromatography. From the cake of the oil ash, protein, reducing sugar and starch contents were determined.