Ad hoc networks are mobile wireless networks which do not have any kind of fixed infrastructure. The routing layer in an ad hoc network ties the network together into a seamless entity and provide transparent services to higher layer protocols. This thesis examines the interactions of two routing protocols, AODV and DSR and how the mobile ad hoc network environment affect TCP performance. The results presented here are as follows: the path length and the presence of competing traffic are the main factors of TCP throughput performance. The size of TCP window affects the loss rate, but the loss rate is not strongly correlated to throughput performance. Using TCP selective acknowledgement option does not improve throughput. Finally, there is hardly any difference in TCP throughput when using DSR and AODV. These conclusions are supported by extensive simulation experiments.