The bacteria involved in an outdoor single phase composting using sawdust and wheat bran as substrates for cultivation of Pleurotus tuber-regium (Fr.) Singer, and Lentinus squarrosulus (Berk.), two Nigerian edible mushrooms were identified. Composting was carried out for 2 weeks. The highest core and peripheral temperatures were 68 and 48ºC, respectively, while the lowest temperature was 32ºC. The highest number of bacteria in the core and peripheral compost were 1.46 x 106 and 6.90 x 105 cfu/ml, respectively. Bacteria isolated and characterized from the fermenting agricultural substrates include Bacillus polymyxa, Enterobacter aerogenes, Micrococcus roseus, Citrobacter freundii, Bacillus subtilis, Clostridium perfringens, Bacillus lichenif...