The invention relates to a method and a device for measuring imbalance in rotors (3) with an asymmetric mass distribution, in particular in asymmetric crankshafts. The system imbalance of the rotor (3) is counteracted by comparison with a compensation shaft (2) that rotates synchronously with the rotor (3). To measure the imbalance, the rotor (3) is connected to the compensation shaft (2) by means of a positive and non-positive coupling unit (14). The invention is characterised in that the coupling unit (14) is designed to be coupled to the standard connection elements (15) on the front face of the rotor (3). The reference angular position (11) of the compensation shaft (2) and the reference angular position (12) of the asymmetrical rotor (3) are detected separately and fed to an electronic evaluation device (13). A correction value for the lead imbalance (9) is calculated in the evaluation device (13) from the difference between the reference angular positions (11,12) and is combined with the measured values of the imbalance that have been calculated or electrically determined.