The new genus Endocomia, ranging from South China to New Guinea, is described, keyed out and discussed among the other four Southeast Asiatic genera of Myristicaceae, viz. Knema, Myristica, Gymnacranthera, and Horsfieldia. Endocomia was formerly included in Horsfieldia under the name H. macrocoma, an ‘aggregate’ species. In Endocomia presently 4 species, one with 3 subspecies, are recognized; of these 2 species and 1 subspecies are newly described. The genus and the species are fully treated taxonomically.