The hermit crab genus Nematopagurus, erected by A. Milne-Edwards & Bouvier (1892) for a single Atlantic species, has vastly larger reported representation in the Indo-Pacific region. However, the majority of species have been described on the basis of one or only a few specimens. The Musorstom expeditions to the south central Pacific and Philippine Islands, supplemented by the surveys of the United States Fish Commission steamer Albatross in Hawaiian, Philippine and Japanese waters, have provided not only a substantial amount of new material, but sufficient representation of most described species to permit the evaluation of intraspecific morphological variation. As a result, although five new species have been recognized, three recently described species have proven to be junior synonyms of previously known, but poorly represented, species. Nematopagurus holthuisi McLaughlin & Hogarth and N. pilosus Komai are synonymous with N. gardineri Alcock, while N. shinnyoae Komai is synonymous with N. kosiensis McLaughlin. The range of N. diadema Lewinsohn, reported previously from the Red Sea, the eastern coast of South Africa, and the South China Sea, has been extended to Fiji, while that of N. meiringae McLaughlin, known from eastern South Africa and the South and East China Seas, has been extended to the Philippine Islands. Nematopagurus kosiensis McLaughlin, previously known only from eastern South Africa has been found not only in Japanese waters, but also as far east as the Hawaiian Islands. Species identified by several authors as N. squamichelis Alcock and N. muricatus (Henderson) have been reexamined and correctly reassigned to other taxa. Descriptions and illustrations are presented for all species, together with a key for their recognition.