The Javan Hawk-eagle Spizaetus bartelsi is globally endangered species which exclusively occupies the last remnant forests of Java island, Indonesia. Studies to explore its distribution throughout the island and to uncover its eco-biology have been going on. Recent field surveys recorded new localities of the Javan Hawk-eagle at South Cianjur, West Java, at G. Sanggabuana, Karawang district, West Java and at G. Endut complex, West Java. Our understanding about this enigmatic bird of prey has been improved. Ecological research, including radio tracking, has provided information on prey species, breeding biology and the estimated home range. Small mammals such as treeshrews, squirrels, bats, rats and other small rodents are the preferred prey, but birds, snakes and lizards are also taken. The Javan Hawk-eagle may breed at anytime of the year but usually between January and July. It is sexually mature at the age of three to four years, breeds every two years and lays only one egg. Incubation lasts for 47–48 days and the young bird is fully fledged at 70 days old. Both parents look after the nestling. Some juveniles stay around the parent's territory until the following breeding season. The home range of non-breeding males monitored by radio tracking at G. Salak and Telaga Warna Nature Reserve, West Java was estimated between 310 and 930 ha. Conservation activities on the Javan Hawk-eagle have been conducted through organizing local training or workshop for awareness and community participation, nest protection programme and regular monitoring. Several local training and workshops have been carried out irregularly in West, Central and East Java. Nest protection programme with the involvement of local community has been successfully run mostly in West Java, e.g. at Cibulao Nature Reserve, G. Salak Protection Forest and G. Gede-Pangrango National Park. Regular monitoring has been practiced at Telaga Warna-Nature Reserve, Gede-Pangrango National Park and in certain area of G. Halimun-Salak National Park.