The chemical composition and bacterial community structure of konoshiro-narezushi were analyzed, the latter by the 16S ribosomal RNA gene clone library method. The respective moisture and the lactic acid concentrations were 62.4% and 1.8%. One hundred randomly selected clones from the clone library were sequenced and analyzed. There were six operational taxonomic units, and the Shannon-Wiener index was1.037. The sequence similarity of all the clones obtained was equal to or higher than 99.6% of the sequence of cultivated bacteria in the public database. Lactobacillus sakei constituted 61% of the clones, suggesting that this bacterium plays an important role in the fermentation of konoshiro-narezushi.