After growing bacteria cells of B. licheniformis strain 2390 in a semisynthetic medium, with different glucose concentrations, it was possible to obtain the start of sporogenesis before the culture reached the maximum growth. The glucose concentrations were from 10 mg% to 1000 mg% and endospores were detected after two days in the incubator at 37ºC with 10mg% of glucose, and nine days when with 1000 mg%¨. The results obtained shown the influence of the carbon source concentrations tested, on the time taked up for the onset of sporogenesis.