Although it is commonly assumed that the use of topology control can improve the throughput capacity of wireless networks, analytical results on this topic are sometimes contradictory and no comprehensive simulation study has been attempted. In this paper, we report the results of a packetlevel simulation-based study of topology control in CSMA/CA networks. The results demonstrate significant throughput increases from certain topology control protocols at moderate to high node densities and high loads. The results indicate, however, that very sparse topologies (e.g. the minimum spanning tree) actually reduce throughput considerably compared to networks without topology control. The results also indicate that, within the range of parameters studied, it is necessary to allow nodes to have distinct transmission powers in order to increase throughput.