The culture of live microalgae to feed larvae and spat is one of the major bottlenecks in bivalve culture. Consequently, there is a strong need for alternative diets to replace live microalgae as food for bivalves in commercial and research hatcheries. This article initially reviews the literature on the nutritional requirements of bivalves and continues with a review of the development of alternative and artificial diets for bivalves. Although a limited number of such diets have been assessed experimentally, their nutritional value is currently limited by a general lack of knowledge of the nutritional requirements of bivalves. The importance of the development of artificial diets, whose nutritional composition can be precisely manipulated, in order to study bivalve nutrition is emphasized. In the absence of clearly defined artificial diets, dietary vehicles such as microcapsules and spray-dried microalgae are currently the most promising tools to study the nutritional requirements of bivalves.