The Phong Nha - Ke Bang National Park (PNKBNP) is situated in Quang Binh province of the north central Vietnam. It was inscribed on the UNESCO World Heritage list in 2003 for its outstanding geomorphological features. The central park area is approximately 860 km2 and contains over 300 known caves. The caves in the area were first explored and mapped in 1990 by a British expedition and this has continued to the present, with expeditions approximately every second year. This has resulted in 17 of the known caves in the Phong Nha area, and 3 in the Ke Bang area being mapped, but to date the fauna has not been investigated, despite the high likelihood of endemic cavemicolous faunal elements. The current preliminary survey aims to provide a basis for future biological surveys in the Phong Nha - Ke Bang World Heritage Area, Vietnam. The current preliminary survey aims to provide an initial overview of the spider fauna in two cave systems: Phong Nha cave system (Phong Nha cave, Tien Son cave), and Dark cave.