Two varieties of cassava stems, YTP1 and H740/92, were collected Biochemical composition of were investigated by determination of total moisture, protein, lipid, cellulose, hemicellulose, crude fiber, starch and soluble sugars. Optimization of medium composition for cellulase enzyme production by Cellulomonas fimi MTCC24 from Manihot esculenta Cranz YTP 1 and H740/92 Stem as the source in submerged fermentation .Effect of different media components such as carbon, nitrogen, and minerals on cellulase production by Cellulomonas fimi MTCC24 in shake flask culture was investigated by one factor at-a-time method. The results indicated that various factors including carbon, nitrogen and minerals, influence cellulase production. The optimum fermentation medium contained a carbon source ((0.3%) pretreated cassava stem), nitrogen ((0.35%) malt extract and (0.25%) ammonium chloride), macronutrients ((0.45%) sodium chloride, Calcium chloride and magnesium sulphate) and micronutrient ((0.001%) manganese sulphate). Under these conditions, the maximum level of cellulase production was observed 8 IU/ml for YTP 1.