Three replicate 4 X 4 factorial trials were conducted with growing-finishing crossbred barrows, fitted with cecal cannulas, to determine the effects of amino acid utilization and specific fiber additions (soybean hulls, sugar beet pulp) to the diet on production of odorous compounds and other odorous compounds from cecal contents, fresh manure and stored manure. Corn-soy diets compared were (1) Diet I: a standard 15% crude protein corn-soy diet with 0.75% total lysine; (2) Diet II: a 11% crude protein corn-soy diet with crystalline 0.39% lysine (.76% total Lys), 0.05% methionine (.25% total Met), 0.05% tryptophan (.15% total Trp) and 0.11% threonine (.51% total Thr) added; (3) Diet III: Diet II with 10% soybean hulls; (4) Diet IV: Diet I with 10% dried sugar beet pulp. Pigs were fed at ad libitum with constant access to water and were housed in the Purdue Animal Sciences controlled environment building. Cecal, feces and urine samples were collected and chemically analyzed. Headspace gas from fresh manure and anaerobically stored manure were analyzed for volatile organic compounds. Cecal ammonia nitrogen was reduced 25% and 19% with the addition of soybean hulls to the low CP diet and the addition of sugar beet pulp to the low protein diet, respectively. The addition of soybean hulls to the low CP diet reduced total cecal nitrogen 24%. The reduced CP diet with supplemental amino acids reduced total urinary nitrogen excretion 28%. The addition of a fiber source to the reduced CP diet showed a 36% reduction in total urinary nitrogen compared to the standard diet. Ammonia nitrogen in fresh manure was decreased 31%, 55% and 47% with the lower CP, lower CP plus soybean hulls and plus dried sugar2 beet pulp diets, respectively. There was 35% less ammonia nitrogen excretion in fresh manure when the reduced CP diet was fed with soybean hulls as a fiber source as compared to the reduced CP diet alone. There was a 38%, 50% and 42% reduction in total nitrogen excretion in fresh manure with the lower CP, the lower CP plus soybean hulls and dried sugar beet pulp diets, respectively. Similar treatment effects were observed with anaerobically stored manure. There was a significant reduction in ammonia and total N with the lower CP diet and synthetic amino acids either alone (37% and 26% reduction for ammonia and 40% to 29% reduction for total N on a wet and DMB, respectively) or with 10% soybean hulls (41% and 39% reduction for ammonia and 34 % and 32% reduction for total N on a wet and DMB, respectively) or 10% dried sugar beet pulp (62% and 64% reduction for ammonia and 43 % and 46% reduction for total N on a wet and DMB, respectively). In addition, on a dry matter basis, sugar beet pulp further reduced ammonia N compared to the other treatments. VFA tended to be lower in stored manure from pigs fed the sugar beet pulp diet compared to the other diets. The addition of soybean hulls and sugar beet pulp reduced benzene, dimethyl disulfide, 2,2-dimethyl hexane and hexane in stored manure. These results suggest that fiber addition to a swine diet and a lower CP diet can help eliminate odorous compounds that may prove to be a nuisance to homes and businesses neighboring swine facilities.