The agglutination of bacterial cells, which are important from the standpoint of food hygiene, was carried out using various phytohemagglutinins (PHAs). The cells of St. epidermidis s-3090, E. coli NIHJ, and S. nagoya were agglutinated by soybean agglutinin (SBA). The cells of Staphylococcus strain were agglutinated by concanavalin A. Agglutinability of the cells was generally correlated with the number of receptor sites for PHA on the cell surface, and the number of ¹²⁵I-labeled SBA bound to E. coli NIHJ was 7.1×10⁵ molecules per cell. It was found that the binding of SBA to E. coli NIHJ was inhibited by D-galactose and the dispersion of the cells agglutinated by SBA was accelerated by the same sugar.