The Louisiade Archipelago, a group of volcanic islands and coral islets, with a total area of approximately 1600 km , lies about 300 km east of the New Guinea mainland and 400 km west of the Solomon Islands. The Louisiades are at least 15-20 million years old and more likely were formed 40-60 million years ago and have apparently never had a land connection with the New Guinea mainland. The archipelagos physical isolation and great age combine to provide considerable opportunity for the evolution of a distinctive fauna. However, this fauna has remained largely unknown, especially for invertebrates, including terrestrial snails. Only a few brief surveys and small collections made in the mid to late 19th century lead to the description of the approximately 35 species of land-snails known from the archipelago. Low sampling intensity and poor geographic coverage combined with high levels of endemism suggest that land snail diversity in the archipelago is under-sampled, a view supported by ten weeks of field surveys in January 2003 and April-May 2004 on the three largest islands in the Louisiade Archipelago: Misima (St. Aignan), Vanatinai (Sudest, Tagula) and Yela (Rossel). These surveys uncovered many undescribed snails, nearly all of them endemic to a single island.