The natural forest in Yanbaru, the northern part of the main island of Okinawa (Okinawa Hontô), is an important area for nature conservation, because it has a large number of endemic animals and plants. First, we explain the status of the most important endemic animals of Yanbaru, stressing that most of them are endangered and near extinction. Second, we show especially high species diversity of trees, insects and mites in the Yanbaru forest. However, the integrity of the Yanbaru forest is seriously threatened by clearcutting and complete removal of forest undergrowth. Although an area in Yanbaru occupied by the US Marine Corps has, to date, preserved good natural forest, a new plan to establish seven military helipads in this area is now being examined. Possible outcomes of such a development are evaluated. In addition, requests by Japanese biologists for the Defence Facilities Administration Agency, Japan to consider alternate sites for the helipads are described.