We present a compilation of all myxomycetes recorded in Papua New Guinea (PNG) and New Caledonia (NC). Specimens were collected during field trips in September 1983 – January 1984 to both territories and in August 1991, October 2007, and April 2009 to NC. Bark and dung samples for moist chamber cultures were collected during the field trips in September 1983 – January 1984 (PNG and NC) and in August 1991 and October 2007 (NC). In addition, information from previous publications and unpublished specimens in the herbarium at the Plant Protection Instituted in Port Moresby, PNG, are included. A total of 180 species are reported. Of the 63 species from PNG 51 are new to the country, and 123 of the 149 species from NC are new to the territory.