This paper includes a revision and description of all species of fresh-water crabs so far known from New Guinea as well as considerations about their geographical distribution. Also their phylogeny is discussed. A new genus, Geelvinkia n. gen., is established and the following new species are described: Rouxana roushdyi n. sp., Geelvinkia ambaiana n. sp., G. holthuisi n. sp. and Holthuisana boesemani n. sp.