We conducted research on mammals diversity in the Mount Sawal Wildlife Reserve on March 2012. Data collection was obtained by direct observation and interviews. They are includes direct encounters, traces/signs of the mammals presence (ex: faeces, traces/footprints, odors, scratch marks, food scraps, etc.) as well as information from the community around the forest. Observations were carried out in seven observation path/forest block in Mount Sawal namely Belandongan, Cibaruyan Jero, Gintung, Gunung Luhur, Kigugula, Jamikuwu, and Sawah Gunung. We documented at least 10 species of mammals have been recorded, including Panthera pardus melas, Presbytis comata, Trachypithecus auratus, Macaca fascicularis, Muntiacus muntjak, Hystrix javanica, Aonyx cinereus, Prionailurus bengalensis, Mydaus javanensis, and Sus Scrofa. The existence of mammals is relatively evenly distributed in all observation path/forest block in The Sawal Mountain. Six species are protected by Indonesian Law, including Panthera pardus melas, Presbytis comata, Trachypithecus auratus, Muntiacus muntjak, Hystrix javanica, and Prionailurus bengalensis. Information on the diversity of mammals is expected to be a scientific consideration in the management area of the Mount Sawal Wildlife Reserve.