Repetitive learning control was examined for active vibration control of rotor. A novel modification of a gradient-based repetitive learning control algorithm was developed. The stability of the algorithm was studied and the algorithm was tested on a rotor test rig. The experiments showed that repetitive learning control attenuated efficiently rotor vibrations excited by rotor unbalances. In addition to experimental work, the paper presents convergence and stability properties of the proposed repetitive learning control approach.