Bacterial strains isolated from water and the black clam Villorita cyprinoides var. cochinensis (Hartley) were tested for resistance to ten antibiotics namely ampicillin, bacitracin, chloramphenicol, gentamycin, neomycin, oxytetracycline, penicillin-G, polymyxin-B, streptomycin and sulphadiazine. Maximum number of strains (95.4%) showed resistance to penicillin. The resistance pattern was found to be Penicillin>Sulphadlazina>Ampicillin>Bacitracin>Streptomycin>Neomycin>PoIymyxin-B:> Oxytetracycline> Chloramphenicol>Gentamycin. The least resistance was offered to gentamycin by all the genera except Flavobacterium/Cytophaga group, which showed least resistance to Polymyxin-B. Strains of Vibrio spp. and Aeromonas spp. exhibited maximum resistance to sulphadiazine, whereas rest of the strains showed maximum resistance to penicillin.