In the United States, Vibrio vulnificus is responsible for 95% of all seafood-born deaths, having a fatality rate of >50%. This pathogen has two distinct genotypes, the C-genotype isolated from human clinical cases and an E-genotype from environmental sources. To investigate if post-harvest temperature has a significant effect on genotype levels, their survival in oysters (Crassostrea virginica) kept at 22ºC (RT) or 4ºC was examined. Oysters (n=25) were exposed to genetically marked strains of the two genotypes of Vibrio vulnificus, E-type of environmental origin and C-type of clinical origin into separate tanks at ca. 7.5 104 7.5 105 CFU per millilitre of tank water, along with phytoplankton. After overnight incubation, oysters were removed and placed at either RT or 4ºC. At this time (0h), five oysters exposed to either V. vulnificus strain were removed to determine the levels of C- and E-genotype uptake. Individual oysters (n=5) were subsequently sampled at 3h, 8h, 24h and 48h (RT oysters), or at 8h, 24h, and 3 and 7 days (4ºC oysters) for each V. vulnificus strain. Experiments were performed twice. After an initial increase (ca. 1.5 logs) of the C-genotype in oysters maintained at RT, cells of this genotype returned to their initial levels, whereas those in oysters maintained at 4ºC decreased nearly 2 logs without an initial increase. No significant differences were detected for cells of the E-genotype in oysters held at room temperature, and this genotype decreased ca. 1.0 log at both RT and 4ºC. These results suggest that the E-genotype may be more resistant to low temperature than are C-genotype cells, and that cold temperatures may result in the relatively higher numbers of the E- in oysters compared to C-genotype.