A device and method for detecting and suppressing double-talk in a cellular mobile unit employ a cellular transceiver; a receive signal path; a transmit signal path; and a double-talk detector. The double-talk detector determines a receive slope of a receive signal, and determines a transmit slope of a transmit signal. The double-talk detector further determines a difference slope of a difference signal that is determined by evaluating differences between the receive signal and the transmit signal. Finally, the double-talk detector generates a double-talk flag signal in the event the transmit slope indicates an increasing transmit speech power, and the receive slope and the difference slope indicate a prescribed relationship between the changes in the receive speech power and the difference power.