Bacterial counts of shrimp delivered by fishing vessels to processing plants varied greatly. Aerobic plate counts at 28 C ranged from 870–1,300,000 per gram. Either natural seawater or distilled water could be used in media preparation. The use of artificial seawater usually resulted in lower counts. The microbial flora of Gulf shrimp was dominated by coryneforms and species of Pseudomonas, Moraxella, and Micrococcus. Refrigerated storage usually caused an increase in Pseudomonas species. Bacterial counts of pond shrimp were much lower than those of Gulf shrimp. In some samples of pond shrimp Bacillus and Lactobacillus species were pre-dominant.