The history of the discovery and naming of specimens now referred to Myoictis is presented. A study of virtually all known specimens of Myoictis deposited in Museum collections was undertaken to clarify the number of species in this genus of endemic New Guinean dasyurid marsupials. Based on a number of morphological features four species are now recognised, namely M. melas, M. wallacei, M. wavicus n.stat. and Myoictis leucura n.sp. The form of the tail readily distinguishes the four species. The distribution of each species has been mapped and no overlap found in their ranges as presently known. Field observations are recounted. Data for all specimens examined is appended to facilitate future studies.