—Time slot assignment is essential to provide the calculated bandwidth in a TDMA (Time Division Multiple Access)-based mobile ad hoc network (MANET), which is a focus of attention of this paper because of its collision-free packet transmission with QoS(Quality of Service) support. In this paper, a new time slot assignment algorithm-SAGO (Slot Assignment by Global Overview) is proposed, by which more available bandwidth can be obtained than conventional approximate solutions. SAGO assigns time slots from a global overview, that is, time slot assignment is based on the usage of global information such as finding of bottleneck of a route, tentative bandwidth evaluation of a route and assignment of time slot according to the order of their free times in the concerned links. In addition, SAGO’s effectiveness is proved by simulation results.