Leaves and stalk samples of Napier grass (Pennisetum purpureum, Schum) cv. Cameroun were harvested at 7 a.m., 10 a.m., 3 p.m. and 5 p.m. The samples were analysed for total soluble carbohydrates and reducing sugars contents. The total soluble carbohydrates contents of stalk were lower at 5 p.m. and the soluble carbohydrates of leaves showed no differences during the day. Reducing sugars content of stalks was maximum at 3 p.m. The reducing sugars/total carbohydrates relation have not showed variations in stalks and leaves during the period considered.