The ability of CO(2) to inhibit respiration and growth of representative strains of seven species of meat spoilage bacteria was examined. Enterobacter and Microbacterium thermosphactum were unaffected by CO(2). Both respiration and growth of the other species were inhibited. With four of the species (fluorescent and nonfluorescent Pseudomonas, Alteromonas putrefaciens, and Yersinia enterocolitica), the inhibition pattern in a complex medium was similar, and inhibition was incomplete and reached a maximum level at comparatively low concentrations of CO(2). With Acinetobacter, inhibition continued to increase with increasing CO(2) concentration. The degree of inhibition with a constant concentration of CO(2) in solution increased with decreasing temperature for all CO(2)-susceptible species except the nonfluorescent Pseudomonas. Anaerobic growth of CO(2)-susceptible facultative anaerobes was unaffected by CO(2).