Three studies were conducted to evaluate the utilization of rice mill by-product using soyabean meal and groundnut cake as protein supplements in the diets of pigs. In the first trial, eighteen (18) crossbred (Large White X Landrace) pigs with average initial weight of 35.9 kg were fed rice by-product at 0, 5 or 10 percent of the 15 percent crude protein diet. Treatments were randomly assigned to each pen of pig in 6 replications. During the 14.2-day trial period, average daily feed (ADF) increased linearly (P/ 0.01) and a quadratic (P/ 0.01) increase was observed for average daily gain (ADG). Feed per unit gain, increased with increasing level of rice by-product. In the second trial lasting 28 days, twelve (12) crossbred (Hampshire X Yorkshire X Landrace) barrows and gilts of average initial weight of 16.5kg were used for digestibility balance trials. Rice by-product was fed at O, 10, 20 or 30 percent of the 18 percent crude protein diet. All pigs were fed at I4. percent and or 6 percent body weight daily. Rice by-product diets fed to the growing pigs depressed gains and feed to gain ratios but did not affect average daily feed intake (ADF). Digestion coefficients for dry matter (DM), N and energy decreased linearly with increasing level of rice by-product. Digestible energy (DE) values of the diets decreased linearly with increasing levels of rice by-product. - viii - in the third trial, twenty four (24) growing-finishing (Landrace x Large White X Hampshire) pigs (barrows and gilts) of average initial weight of 3 5.5 kg liveweight were fed for 56 days with graded levels of rice by-product to test its effects on performance and carcass characteristics. Rice by-product replaced 0, 15, 30 or 45% of the maize in iso-nitrogenous pig finisher diets. Animals were slaughtered in three sequential groups beginning with the first two replicates. Performance data was based on 56 days while animals were on the experimental diets prior to slaughter. Carcass measurements were taken. Results showed significant differences among treatments with respect to average daily gain (ADG), efficiency of feed utilization and carcass weight, but the average daily feed (ADP) and digestible energy intakes were not significantly affected during the period. Generally, pigs on the control diet , tended to perform better than those on rice by-product diets, but the differences were not always statistically significant. Carcass quality measurements did not show significant differences among treatment means, but there was a tendency towards lower fat plus skin measurements and higher lean parameters as the levels of rice by-product increased in the diets. It is suggested that rice by-product can be economically used to replace the more expensive maize component at most up to 30 percent level tested in this trial without adversely depressing the performance of growing-finishing pigs.