This paper proposes a new acoustic echo cancellation (AEC) system which combines a conventional AEC algorithm with the pitch analysis technique. Departing from the use of pitch prediction in speech coding, we use two signals, i.e. the estimated echo and the residual echo, to fulfill the pitch extraction in the AEC system. This system is suitable for the applications of digital networks where the nonlinearities of the echo path significantly degrade the performance of conventional AEC algorithms. Simulation results using a nonlinear channel show that, compared to conventional AEC algorithms, the proposed system remarkably suppresses the acoustic echo during double-talk.