The warm water and high primary productivity of tropical estuaries allows for rapid growth and production of bivalves, but sanitary quality of molluscan shellfish poses one of the single largest impediments to development of international markets. The regulations of the US Food and Drug Administration (FDA) are outlined as representative of regulations governing international trade of fresh and frozen molluscan shellfish. The status of shellfisheries and molluscan aquaculture in several tropical and subtropical nations is presented. A number of developing nations, including Mexico, Peru and the Philippines, have established export markets for fresh scallop adductor meats because they are not considered to be a public health risk. Developing countries, including Mexico, Chile and Korea, export other bivalves by maintaining sanitary water quality in shellfish-growing areas. The inadequacy of coliform bacteria as indicators of shellfish hygiene in tropical waters necessitates research and development of alternative water quality indicators. Strategies for raising shellfish sanitary quality prior to marketing are presented, including transplant or relay, depuration and irradiation of the shucked product. Depuration is especially useful in lowering the risk of environmental, non-faecal pathogens such as Vibrio and can provide extra time between harvest and marketing, to allow public notification in the event of toxic algal blooms.