This study clarifies the effects of network complexity and network map transformation on the ability of network managers to use graphic network displays. Maps of Japan and the United States with outlines of their respective prefectures or states were displayed on a CRT. Each map displayed a fictitious network of nodes and their interconnections. These networks were two-level hierarchical and non-meshed, meaning that each low-level node was connected to a single high-level node, but not all high-level nodes were linked together. The subjects, task was to identify a path between two low-level nodes. In each trial, two low-level nodes were highlighted, and the subject attempted to find the shortest path between these nodes. This was done by using a mouse to select intermediate nodes. Completing a path required a minimum of 4 node traversals. Three variables were manipulated. First, the number of nodes was defined as the total number of low-level nodes in a network (70, 150, or 200). The second variable was the level of transformation. Very densely populated areas of the maps were systematically transformed to reduce congestion. There were three levels of transformation. The final variable was the country map used, that is, the map of Japan and the map of the United States. Several behavioral measures were used. The most informativ. appeared to be the time required to complete a path (the response time), and how often subjects returned to previous portions of a path (back-ups). For both of these measures, the data pattern was essentially the same. Increasing the number of nodes hurts performance. This was particularly pronounced when the map of Japan was tested. However, as the level of transformation increased, this effect was substantially reduced or completely eliminated. The results are discussed in terms of engineering rules and guidelines for designing graphical network representations.