Studies on diet varieties and feeding activities of ten species of brachyuran crabs and their contribution in the nutrient cycle at coastal belt of Midnapore (East), West Bengal, India has established the significant roles played by grapsidae crabs Sesarma (Chiromantes) bidens , S. taeniolatum and Metopograpsus maculatus along with other brachyurans viz. Uca acuta acuta , U. lactea annulipes, U. triangularis bengali, Ocypoda macrocera, Dotilla blanfordi, Dotillopsis brevitarsis and Metaplax intermedia. Organic matter especially the mangrove plant litters after being processed by crabs could form the basis of a coprophagous food chain involving small invertebrates, or be re-exported as micro-particulates. Different nutrient contents viz. organic carbon, available phosphorus, available potassium and available nitrogen analyzed from the gut contents, excavated soils and soils surrounding burrows of the studied brachyuran species were found to show seasonal variability’s and also significant differences among different species.