This study was performed to improve acidogenic fermentation of food waste in a continuous-flow reactor. The fermentation of food waste is affected by the fermentation constraints such as the biodegradability of substrate, the degrading capability of microorganisms and the environmental conditions. The key factors were, therefore, examined to control the fermentation constraints, such as the effect of seed inoculation and the effect of adjusting dilution rate. Acidogenic fermentation of food waste employing rumen microorganisms resulted in the enhanced efficiency (71.2%) as compared with that (59.8%) employing mesophilic acidogens. In addition, the fermentation efficiency increased from 71.2 to 82.0% by adjusting dilution rate from 3.0 to 1.0 d(-1) depending on the state of the fermentation. The main component of the acidified product was shifted from butyric to acetic acid. This meant that the increase of the fermentation efficiency was mainly caused by the enhanced degradation of vegetables and meats. The control of the fermentation constraints was, therefore, very effective in improving the fermentation efficiency of food waste.