A world catalogue and taxonomic keys of the subfamily Nicomachinae (Polychaeta: Maldanidae) are provided. Three genera and 32 species are listed, complete with original references, synonyms, additional references, type localities, and taxonomic remarks for those species which present some problem. Nicomache interstricta Ehlers, 1908 is transferred to the genus Lumbriclymene Sars, 1872. Nicomache inornata Moore, 1903, Petaloproctus crosnieri Rullier, 1964, and Petaloproctus crenatus Chamberlin, 1919 are considered incertae sedis. Only three species of Nicomachinae have a broad geographical distribution.