Only fragmental studies have been done regarding the taxonomy of Japanese meiofauna. This fact however does not necessarily mean meiofauna is not interesting to work. 0n the contrary, meiofauna can be regarded as treasuries of new taxa. Millions of meiofaunal species such as nematodes are yet to be described from the Japanese waters. The background, e.g. literature, to carry out taxonomy of meiofauna has been consolidated now. As the next step, we need to organize an international collaboratory program to investigate the meiofauna in the western Pacific region.