It is commonly found that males show a higher susceptibility to infectious diseases. While the underlying mechanism for this sex difference is not fully understood, one significant contributing attribute is the presence of specific sex hormones- e.g. Testosterone, Estrogen, and Progesterone. These hormones have been shown to moderate immune function in both protective and suppressive capacities. These sex steroids also have a direct effect on bacterial metabolism, although the range of responses (proliferation or inhibition) appears to be bacterial species-specific. Vibrio vulnificus is one example of a bacterium that produces an infection exhibiting a significant sex difference, with 85% of cases being male. Previous studies have suggested that the presence of estradiol protects against endotoxic shock caused by the lipopolysaccharide (LPS) of this bacterium, however, no studies have investigated the direct and indirect role of steroid hormones on the viability and proliferation of this bacteria in the bloodstream. The present study uses serum from rats as a model for septicemic infections. These sera were treated with different ratios of endogenous and exogenous sex hormones to determine the indirect and direct effect of viability of V. vulnificus in each condition, and survival assessed at various time points following bacterial inoculation. Results indicate that presence of hormones in the sera do not appear to be a regulatory element for survival of this bacterium continuously. After 24 hours, there were no significant differences observed among any of the experimental groups. There do appear to be minor significant variations of proliferation for one ratio and time and in male and female sera at early time points. The data presented gives us a further understanding the influence sex steroids may have on the viability of V. vulnificus, and suggests the investigation of alternative indirect effects of these hormones.