A method is provided for balancing rotors (10) of electrical machines. Each rotor (10) has a shaft (11) and at least one laminated core (12) is arranged on the shaft. The method includes providing blanks (13) with a length (l) that is smaller than an outside diameter (d) of the laminated core (12) of the rotor (10). A magnitude and orientation of an initial unbalance of the rotor (10) then is ascertained. A recess (15) then is made in each blank (13) spaced from the center of gravity by a distance depending on the magnitude of the ascertained initial unbalance. The blank (13) is mounted by fitting the recess (15) on the shaft (11) of the rotor (10) and mounting the processed blank (13) on the rotor (11) in an angular position that is dependent on the orientation of the ascertained initial unbalance.