Four laboratory-scale anaerobic baffled reactors (with two, three, foul; and five chambers, respectively) were used to successfully treat whole swine waste. The baffled reactors did an excellent job of trapping the small diameter methane-containing particles of proteins, cellulose, hemicellulose, and lipids. Solids retention times of 25, 30, 36, and 42 days were achieved with a corresponding hydraulic retention time of 14 days for two-, three-, four- and five-chamber anaerobic baffled reactors, respectively COD reductions ranged from 70 to 78% among all the reactors studied. Maximum methane production was observed in the reactors with four and five chambers with a value of 0.59 and 0.62 l/g of volatile solids added at a loading of 4 g VS/l/day, respectively.