A method and apparatus for performing transmit (Tx) power control in a convergence network of a plurality of communication systems. A method for performing transmit power control (TPC) in a plurality of communication system convergence networks includes receiving, by a first entity of a first communication system, a TPC information request message requesting information associated with transmit power control (TPC) from a second entity of a second communication system; upon receiving a request of the TPC information request message, transmitting a first TPC information reporting message, which includes a maximum transmit (Tx) power value of the first entity and an interference signal value caused by a neighbor entity of the first entity, to the second entity; receiving a TPC command message, which includes information of the maximum Tx power value of the first entity adjusted based on the maximum Tx power value of the first entity and the interference signal value, from the second entity; and adjusting the maximum Tx power value of the first entity based on the information regarding the adjusted maximum Tx power of the first entity.