The theoretical aspects of reproductive strategies and life histories are analyzed. The gonadal structures and the main features of gametogenesis of bivalves and echinoids are described. Research on the reproductive characteristics and gametogenic cycles of the bivalve molluscs in the Argentinian littoral and the echinoid Loxechinus albus is reviewed. Special references to Mytilus edulis, Aulacomya ater, Brachidontes purpuratus, Aequipecten tehuelchus, Zygochlamys patagonica, Ostrea puelchana, Clausinella gayi, Protothaca antiqua, Eurhomalea exalbida and Mesodesma mactroides are made. Analysis of reproductive cycles includes histological and ponderal descriptions of gonadal variations. The main trend found is the partial and multiple spawning episodes. Sexual variations in dioecious and hermaphroditic species are discussed. Calvo, J.; Morriconi, E.; Orler, P.; 1998. Estrategias reproductivas de moluscos bivalvos y equinoideos. En: Boschi, E.E.; ed. Los moluscos de interés pesquero. Cultivos y estrategias reproductivas de bivalvos y equinoideos. Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero INIDEP, (El Mar Argentino y sus Recursos Pesqueros; 2 ) p.195-231. Published Aulacomya ater, Brachidontes purpuratus, Clausinella gayi, Loxechinus albus, Mesodesma mactroides, Mytilus edulis, Ostrea puelchana, Pandalus montagui, Zygochlamys patagonica, ciclo de vida, reproducción, moluscos marinos