The invention is directed to a method for operating a pitch-controlled wind turbine having a rotor blade adjustable about its longitudinal axis and having a generator wherein a set-point for a generator torque (M) is specified in dependence upon a rotational speed (n) of the generator or of the rotor. A transition point (n3, M3) is provided whereat a switchover occurs from a part-load operation to a full-load operation. In the method, a value for air density (ρ) is determined and a pre-pitch angle (φpre) is set starting at a pre-pitch rotational speed (n4) less than the rotational speed (n3) at the transition point (n3, M3). The value of the pre-pitch angle (φpre) is dependent on the value determined for the air density (ρ) so that a larger pre-pitch angle is set when the air density is lower than when the air density is higher.