Throughout the feudal era up until the early 1970s a traditional management system was in effect in eastern Indonesian areas. However, this system was steadily replaced by centralized government control. This transformation had two impacts: (1) it resulted in conflicts among fishers regarding resource use; and (2) overexploitation of fisheries occurred in some fishing grounds. Recently, however, there has been a growing interest in reconsidering the adoption of the traditional system of fisheries resources management, with a slight modification towards a co-management system. Based on case study data this article describes the practice of traditional management of communal-property fisheries resources with particular reference to the Sasi system. The Sasi system is considered as effective in protecting and conserving fisheries resources in the coastal waters of a community. The continued existence of the system is supported by three elements: (1) a well-established traditional community organization; (2) an informal government endorsement of the Petuanan territory as a communal-property right; and (3) an attitude of compliance and cultural value attributed to the familial relationships existing among fishers.