Lactic acid bacteria and particularly Lactococcus lactis are widely used for the production of lactic acid in fermented foods. Control of the catabolic rate in L. lactis, i.e., the rate of lactic acid production, appears to be determinant for dairy product quality. While the mechanisms involved in control have not been totally elucidated, they seem to depend upon the strain and the growth conditions. Furthermore, it remains unclear whether the catabolic rate is controlled at the level of transcription, translation or enzyme activity. The recent sequencing of the L. lactis genome has brought novel insights to physiologic studies of the bacteria. This review discusses both genetic information and metabolic studies concerning anaerobic sugar catabolism in L. lactis.