Disclosed is a method of reducing a structural unbalance in a wind turbine rotor with pitch control and a control device for performing. A frequency component is detected resulting from the structural unbalance in the wind turbine rotor on the basis of the rotor speed signal. The multiplying the frequency component signal is multiplied by a complex correction factor. Individual pitch angle offsets are establishing for each blade of the rotor based on the magnitude and the phase and complex correction factor. Individual pitch angle offset are added to the respective pitch angles of the blades of the rotor.