Abstract—The adaptive algorithms used for acoustic echo can-cellation (AEC) have to provide 1) high convergence rates and good tracking capabilities, since the acoustic environments imply very long and time-variant echo paths, and 2) low misadjustment and robustness against background noise variations and double-talk. In this context, the affine projection algorithm (APA) and different versions of it are very attractive choices for AEC. However, an APA with a constant step-size parameter has to compromise between the performance criteria 1) and 2). Therefore, a variable step-size APA (VSS-APA) represents a more reliable solution. In this paper, we propose a VSS-APA derived in the context of AEC. Most of the APAs aim to cancel (i.e., projection order) previous a posteriori errors at every step of the algorithm. The proposed VSS-APA aims to recover the near-end signal within the error signal of the adap-tive filter. Consequently, it is robust against near-end signal varia-tions (including double-talk). This algorithm does not require any a priori information about the acoustic environment, so that it is easy to control in practice. The simulation results indicate the good per-formance of the proposed algorithm as compared to other mem-bers of the APA family. Index Terms—Acoustic echo cancellation (AEC), adaptive filters, affine projection algorithm (APA), variable step-size affine projec-tion algorithm (VSS-APA). I.