Materials of three nephtyid genera,
Inermonephtys,
Micronephthys and
Aglaophamus from Japanese waters were examined. Ten species or subspecies and one indeterminable species are recognized; they include four new species,
Aglaophamus japonicus,
A. lobatus,
A. amakusaensis and
Inermonephtys japonica and one new subspecies,
Aglaophamus gippslandicus bisectus. The holotype of
Aglaophamus jeffreysii Mclntosh, 1885 collected from Japan was re-examined.