Abstract: In an attempt to upgrade the traditional fermentation technology of soybean into daddawa, the effect of fermentation temperature on the biochemical and organoleptic properties of soy-daddawa produced by starter culture was studied. Bacillus subtilis SDA3 previously selected as a good starter for soy-daddawa production was used to ferment sterile dehulled cooked soybeans at 25, 30, 35 and 40°C for 72 h. The viable cell counts of B.subtilis SDA3 increased throughout the 72 h fermentation process at 25 to 35°C while the counts decreased after the 24th h at 40°C fermentation. pH value increased throughout the fermentation with a rather low increase in the fermentation at 25°C. Relative proteolytic activity increased with fermentation, attained a peak at 48 h and then dropped in fermentations at 30-40°C. Proteolytic activity which was not detected by the 12th h increased thereafter till the end of the fermentation at 25°C. Free amino acid content increased throughout the 72 h fermentation at 30-40°C while an initial drop was observed in the first 12 h with subsequent increase till the end of the fermentation at 25°C. Alpha amylase activity increased, attained a peak at the 48 h and then dropped in 30 and 35°C fermentations. Alpha amylase activity increased throughout the 72 h fermentation at 25°C while at 40°C, the activity attained a peak at the 24th h and then dropped. Fermentation at 35°C gave the highest levels of proteolytic and alpha amylase activities, pH and free amino acids in soybean inoculated with B. subtilis SDA3. Organoleptically, soybean fermented by B. subtilis SDA3 at 35°C produced the best quality soy-daddawa as judged by a panel of regular soy-daddawa consumers. Fermentation at 35°C was therefore chosen as the optimised temperature for the production of soy-daddawa by B. subtilis SDA3 starter culture.