Building a forest road network is an important task for the forest manager Such a road network must be designed to minimize both the cost of construction and the operational cost. To find optimal locations for the road network, many forest engineers still use traditional methods that are almost entirely manual. Several attempts have been made already on the use of GIS for forest road network optimization in Indonesia and elsewhere. This paper deals with the evaluation and comparison of several methods and the research of the most efficient one for forest management purpose. We consider that a network is optimal if the cost of the construction is minimal. More specifically, the aim of our research conducted for a tropical forest concession in Central Africa (1.500 ha), is to plan an optimal forest road network to access logging areas, taking into account topographical and hydrographical constraints (slopes, swamps, wide rivers). Following Setyabudi (1994) and Dean (1997), an automated method is applied using IDRISI, a raster based Geographical Information System. Three methods are investigated, all of them based on the same principle of calculating a cumulative distance cost (Eastman, 1995) and applying a Pathway Analysis. In the simplest way, logging areas are considered as independent, unlike the second one for which an iterative process is used: the network is then built step by step. The lost method is more sophisticated which takes into account the nodes of the network (number and location). Finally results generated by these three methods are assessed in term of cost and compared to manual delineation.