Crabs and molluscs are the predominant animal groups of the mangrove ecosystems and they play a significant role in the structure and functioning of the ecosystems. Number of crab species found in the different climatic areas varies from one another . Ashton et al. 2003 have recorded 31 species of crab species from Sarawak mangrove in Indonesia. The number of species recorded in the present study is low compared to those recorded by Sasekumar 1974, Firth et al 1976 and Ashton et al .2003 in different study areas. This study has identified two crab species, namely Sersarmar guttatum and Metopograpsus thukuhar which were not recordeded from Sri lanka earlier.