Provided are a method and an apparatus for transmitting a message in a dual mode terminal which supports a mobile communication network and a wireless Internet network. If an event for transmitting the message occurs in a mode supporting the mobile communication network, it is determined whether the wireless Internet network exists in a current position of the dual mode terminal; if it is determined that the wireless Internet network exists in the current position of the dual mode terminal, the mode supporting the mobile communication network is changed into a mode supporting the wireless internet network; and the message is transmitted through the wireless Internet network.