A method and an acoustic signal processing system for noise reduction of a binaural microphone signal are proposed. A source signal and two interfering signals input to a left and a right microphone of a binaural microphone system respectively. A left and a right microphone signal is filtered by a Wiener filter to obtain binaural output signals of the source signal. The Wiener filter is calculated as H W ⁡ ( Ω ) = 1 - S y ⁢ ⁢ 1 , y ⁢ ⁢ 1 ⁡ ( Ω ) S v ⁢ ⁢ 1 , v ⁢ ⁢ 1 ⁡ ( Ω ) + S v ⁢ ⁢ 2 , v ⁢ ⁢ 2 ⁡ ( Ω ) , wherein Sy1,y1(Ω) is the auto power spectral density of the sum of the interfering signals contained in the left and right microphone signal, Sv1,v1(Ω) is the auto power spectral density of the filtered left microphone signal and Sv2,v2 is the auto power spectral density of the filtered right microphone signal. The method provides the advantage of an improved binaural noise reduction compared to the state of the art with small or less signal distortion.