An electronic noise attenuation system for attenuating a sound wave propagated from a source of noise by generating another sound wave 180.degree. out of phase and having the same sound pressure with the propagated sound wave from electro-mechanic transducer means disposed in a propagation passage of sound waves. In the electronic noise attenuation system, a drive signal for drive the electro-mechanic transducer means is generated in accordance with output signals respectively output from upstream-side and downstream-side mechano-electric transducer means respectively disposed in the propagation passage with the electro-mechanic transducer means therebetween. Namely, the drive signal is created by performing an operation on a difference signal between the output signal of the upstream mechano-electric transducer means and the drive signal according to a given transfer function. Also, the transfer function is determined in accordance with the difference signal and the output signal of the downstream mechano-electric transducer means.