The economic importance of mariculture in less developed countries (LDCs) and their development plans are discussed. The basic processes involved in mariculture are outlined and some of the species maricultured in LDCs are considered. Factors which are important in assessing the suitability of a species for mariculture in developing countries are highlighted. These include consumer acceptance, biology, environmental, technological and economic factors. The economic success or otherwise of a species for mariculture depends upon all the factors as well as others.