The Lake Kutubu Wildlife Management Area (WMA) covers approximately 23,500 ha of freshwater lake and surrounding forest environments on the southern slopes of New Guinea's central cordillera in mainland Papua New Guinea (PNG). Ornithological work within the WMA spans more than 50 years, although most of the data are available only in the grey literature and are difficult to obtain. In light of a proposed review of PNG's protected area network, we collate bird records from the WMA and draw upon data from the nearby Agogo Range to consider the potential for additional species to occur within the gazetted area. The WMA inventory stands at 216 species, nearly one-third of all species resident or regularly occurring in the New Guinea region. The high species richness is attributable to the presence of a variety of forest and wetland habitats spanning nearly 600 m elevation, supporting bird species characteristic of lowland, hill and lower montane environments. Resident avifauna include five IUCN threatened or Near Threatened species (New Guinea Harpy Eagle Harpyopsis novaeguineae, Gurney's Eagle Aquila gurneyi, New Guinea Vulturine Parrot Psittrichas fulgidus, Striated Lorikeet Charmosyna multistriata and Banded Yellow Robin Gennaeodryas placens) and the restricted-range Greater Melampitta Megalampitta gigantea. Geographic and elevational range extensions are reported for numerous taxa, and recent data are presented to better document the distributional relationships of species pairs in the genera Talegalla, Megapodius, Micropsitta and Lonchura, and of races of Brown Cuckoo-Dove Macropygia amboinensis and Double-eyed Fig Parrot Cyclopsitta diophthalma.