A complete list of genera and species of the order Mysidacea, known at present is given. The latitudinal occurrence, range in body length, geographic region and habitat of each species are described on current information. The source of a good description, is quoted for every species. There are at present some 765 species distributed between about 120 genera. There is no indication that the world list of species is nearing completion because many new species are being described each year. Mysids are predominantly coastal organisms and detailed sampling of the coasts of Africa, South America, Australasia and Oceania may result in many further new species and records.