For revealing a role of Coprothermobacter spp. in anaerobic digesters, a novel strain was isolated from a cattle manure digester and its characteristics were compared with those of known Coprothermobacter species. The new isolate, a strain IT3, has a different habitat of higher temperature conditions than type strain BTT. At 60 ℃ condition, strain IT3 shows aggregation of independent cells, while for strain BTT formation of short filament. μmax(hr-1)values at 70℃ were recorded as 0.273 for strain IT3 and 0.217 for strain BTT. Hydrogen production of each strain IT3 and BTT was similar but peptidase activity of strain IT3 was 4 times higher than that of strain BT. Coprothermobacter spp., especially Coprothermobacterproteolyticus, have ability to produce hydrogen and carbon dioxide from many kinds of bioresources, and this study indicates that the bacteria work as important players in the preprocess of methane and hydrogen fermentation.