Microbial production of β-amylase by Aspergillus niger (NCIM 1248). Aspergillus oryzae (NCIM 640) and Bacillus subtilis (NCIM 2439) were studied using ragi flour as a source of energy. The culture medium was analyzed for total plate count, contents of starch, non-reducing and reducing sugars and enzyme activity six hours up to 72 hrs of incubation period. The concentration of non-reducing and reducing sugars decreased and the percent consumption of starch increased with the fermentation time in all three cases. Incubation period of 72 hours was required in submerged fermentation to obtain, maximimum growth, product formation. Similarly maximum-β-amylase was observed after 72 hrs of fermentation liberating 0.99, 0.74, 0.87 (mg/ml) of maltose by A. niger, A. oryzae and B. subtilis respectively.