A method and an apparatus for damping voltage oscillation of a voltage intermediate circuit of a frequency converter, the frequency converter comprising a half controlled rectifier bridge coupled to a supply network. The method comprises determining magnitude (Uc) of voltage of the voltage intermediate circuit, determining magnitude (Uin) of rectified voltage of the supply network, forming a derivative of a difference (Uin−Uc) between the rectified voltage of the supply network and the voltage of the voltage intermediate circuit, delaying firing of controllable components of the rectifier bridge on the basis of the formed derivative.