This paper presents a novel technique for diagnosis of unbalance at the terminals of an induction motor, which is based on continuous measurement of phase differences between the waveforms of three line currents fed to the motor stator wherefrom the existence of unbalance as well as its degree are obtained. Theoretical background of the technique has been presented in the text followed by experimental validation. The novelty of this scheme is that without actually measuring the negative phase sequence current, the degree of unbalance can be detected and hence use of sequence filters are avoided.