The effect of dose-dependent gamma irradiation and subsequent cold storage on bacteriological profile of tissues derived from Scylla serrata was evaluated. Irradiation at 0.5, 1.0 and 2.0kGy significantly reduced the (P=0.0001) total plate count (TPC) by 1.0, 2.0 and 2.5 log units, respectively. Treatments of 1.0 and 2.0kGy irradiation reduced total coliform (TC) count below 1most probable number (MPN)/g in the muscle and hepatopancreas and below 50MPN/g in the gills of S.serrata. Irradiated tissues stored at -20C showed significant reduction in TPC and TC. Bacillus spp. was predominant in the tissues before and after gamma irradiation. While live crab tissues harbored both gram-positive and gram-negative bacteria in equal proportion, more than 90% of them from irradiated tissues were gram-positive. Biochemical and 16S rRNA gene-based study on generic composition of heterotrophic bacteria revealed fairly good diversity in nonirradiated tissues and the dose-dependent gamma irradiation significantly reduced their diversity concomitantly. © 2015 Wiley Periodicals, Inc.