Digestive enzymatic compositions and activities in digestive diverticula of the three species of bivalves were investigated in this study. Mytilus galloprovincialis, Saxidomus purpuratus and Tegillarca granosa which were collected from southern coast of Korea on November 2010, were used for analysis. Amylase and cellulase occupied approximately 95% of digestive enzymes in digestive diverticula of M. galloprovincialis, S. purpuratus and T. granosa. The amylase and cellulase activities were 2.6 and 0.8 U/mg in M. galloprovincialis, 2.4 and 8.8 U/mg in S. purpuratus and 7.3 and 11.8 U/mg in T. granosa. And protease activities in digestive diverticula of M. galloprovincialis, S. purpuratus and T. granosa showed the lowest values to 0.00019, 0.00028 and 0.00022 U/mg, respectively.