Abstract Two new species of the endemic New Guinea rodent genus Leptomys Thomas, 1897, are described: L. paulus, indigenous to the montane forests in the Owen Stanley Range in eastern New Guinea, and L. arfakensis, known only from the Arfak Mountains on the Vogelkop Peninsula in western New Guinea. These descriptions are presented within a taxonomic review of Leptomys based on all known specimens in collections of the world's museums. In addition to the new species, the morphological attributes and geographic distributions of three others are documented. Leptomys elegans occurs in southcentral and southeastern New Guinea both north and south of the Central Cordillera, ranging from the Kikori River Basin in the west to the southern slopes of the Owen Stanley Range, then extending round to the north side of the Cordillera in the Maneau Range, and in the outlying highland block of Mount Victory. Leptomys signatus is recorded only from the Fly and Kikori River drainages south of the Central Cordillera. Leptom...