Large and growing segments of the U.S. population consume seafood or engage in marine recreation. These activities provide significant benefits but also bring risk of exposure to marine borne illness. To manage these risks, it is important to understand the incidence and cost of marine borne disease. We review the literature and surveillance/monitoring data to determine the annual incidence of disease and health consequences due to marine borne pathogens from seafood consumption and beach recreation in the United States. Using this data, we employ a cost-of-illness model to estimate economic impacts. Our results suggest that health consequences due to marine borne pathogens in the United States have annual costs on the order of $900 million. This includes $350 million due to pathogens and marine toxins specifically identified as causing food-borne disease, an estimated $300 million due to seafood borne disease with unknown etiology, $30 million from direct exposure to Vibrio vulnificus, V. parahaemolyticus and V. alginolyticus, and $300 million due to gastrointestinal illness from beach recreation. Although there is considerable uncertainty about the degree of underreporting of certain pathogen-specific acute marine-related illnesses, the conservative assumptions we have used in constructing our estimate suggest that it should be considered a lower bound on true costs.