A mobile communication terminal and a voice input/output method for inputting/outputting voice during playback of music data by using a Bluetooth communication scheme are disclosed. The method includes connecting to a headset via a simplex channel according to the Bluetooth communication scheme when music data is played; determining if a call has been connected; terminating current connection to the headset via the simplex channel and connecting to the headset via a duplex channel according to the Bluetooth communication scheme while maintaining the playback of music data when the call has been connected; mixing decoded music data with data obtained by decoding incoming voice data received from the communication partner as a result of a call connection; and outputting the mixed data to the headset via a transmission channel of the duplex channel and receiving originating voice data of the user from the headset via a reception channel of the duplex channel.