Staph. aureus, Staph. albus, Strep. hemolyticus, D. pneumoniae, A. aerogenes, M. luteus, all taken from the depaqtmental stock, were used throughout this work as tested bacteria. The author divided these organisms in two groups, one contained Staph. aureus an Staph. albus, the other Strep. hemolyticus, D. pneumoniae, M. luteus; made any possible combinations of 2 strains between both groups; and observed the interaction between 2 strains on the growth and the oxydative degradation of glucose when cultured in the liquid media containing glucose. The following results were obtained. 1) The bacterial growth of combined inoculation tended to be inferior than the pure culture of either strain. Comparing with control, the growth was also inferior in the case ot pure culture into which media added the cell fue supernatant separated from the culture of other strain. 2) However, it was observed much consumption of glucose by the eombined culture of bacteria than by the pure culture. And the same was said concerning with the accumulation of glucose metabolite; pyruvate, lactate and acetate. This tendency was also demonstrated in the culture into which media the supernatant of others was added. 3) Hence, it was postulated that two strains in the combined culture interacted cooperatively in degradation of glucose so far as resulting in pyruvate; but, contrasted to that, competitively in further degradation of pyruvate.