SUMMARY: Working details are given of a method for producing streptomycin by the surface culture of Streptomyces griseus in pint milk bottles on a papain digest of beef+meat extract+glucose+mineral salt medium. Streptomycin titres in the crude culture filtrates of 250 μg./ml. or more were obtained after 10-14 days' growth. Evans's peptone, papain digest of spent pancreas from insulin manufacture, papain digest of yeast, and a proprietary casein-meat hydrolysate were found to be possible alternative sources of organic nitrogen. Growth was good on media containing peptic digest of beef or peptic-tryptic casein digest, but the streptomycin there was low. The utilization of glucose and the production of streptomycin depended on the relative amount of nitrogen present in the medium.