Aerobic plate counts of fresh pond-reared shrimp (Penaeus stylirostris, Penaeus vannamei, and Penaeus setiferus) ranged from 1.5 × 103 to 1.3 × 104 per gram. Coryneform bacteria and Vibrio spp. dominated the microbial flora of shrimp. Aerobic plate counts of pond waters ranged from 6.1 × 102 to 2.2 × 104 per milliliter. Vibrio spp. usually were dominant in pond waters. Enterococci and coliform levels in shrimp were low. Fecal coliforms were present in only one of 11 shrimp samples. No Escherichia coli was recovered from pond-reared shrimp. Salmonella, Vibrio parahaemolyticus, Bacillus cereus, and Clostridium perfringens were not recovered from either shrimp or pond waters. No relationship could be established between changes in numbers and types of microorganisms in pond-reared shrimp or pond waters and changes in characteristics of the pond waters such as temperature, salinity, dissolved oxygen, and pH.