Glycoconjugates were identied in many marine organisms, in which they are involved in immune response, thrust generation in nonagellar cyanobacteria, electroreception in sharks, sperm-oocyte interaction, cell recognition in embryo development, and cell adhesion (Caldwell and Pagett 2010). Moreover, reproductive biology is one of the areas within marine science that has a pronounced glycoconjugate component (Caldwell and Pagett 2010). Nevertheless, there has been very little

emphasis on glycobiological studies in reproduction, as the great majority of these studies have been focused on gametes and fertilization. Although little is known about the function of glycoconjugates in gametogenesis in marine organisms, it is better characterized in the fertilization process. This chapter aims at highlighting recent advances on the key role of glycoconjugates in gametogenesis and fertilization process of marine animals.