The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing glucose and (NH4)(2)BPO4, the strain could convert 137.0g of glucose into 52.4g of 2,3-butanediol and 8.4g of acetoin in shaking flasks. The diol yield amounted to 90% of its theoretical value and the productivity was 1-1.5g.L-1.h(-1). In fed-batch fermentation, the yield and productivity of diol were further enhanced by maintaining the pH at 6.0. Up to 92.4g of 2,3-butanediol and 13.1g of acetoin per liter were obtained from 215.0g of glucose per liter. The diol yield reached 98% of its theoretical value and the productivity was up to 2.1g.L-1.h(-1).