Swine manure has a very high pollution potential and obnoxious odor. Large farms particularly are confronted with a manure disposal problem since environmentally acceptable solutions are now required by government regulations. Swine manure was found to be a good source of supplementary nutrients to ferment wheat straw into single-cell protein (SCP) with Chaetomium cellulolyticum when 0.13g (NH4)2SO4/g solid was used as an additional source of N. In batch fermentations, inhibitory effects, possibly due to soluble released from the straw during alkali or acid pretreatment, were overcome by starting the fermentation at about pH 7.0 and then reducing it to 5.0 during growth. An overall protein productivity of up to 66 mg/L h was obtained from a slurry mixture of 1% w/v solids of manure and straw. This compares favorably with 99 mg/L h when manure was fermented with glucose instead of straw as the main carbon source. A high protein productivity of 200 mg/L h was obtained from a slurry mixture containing anaerobically prefermented swine manure liquor and 1.5% w/v solids from straw. The final products of the manure and straw fermentations contained 25-30% DW crude protein and 6-20% DW cellulose and the materials were free of the original obnoxious odor and undesirable microbial contamination.