The effect of partial rotor-to-stator rubbing is investigated both experimentally and analytically. It is found that due to rubbing the measured vibration signal is distorted showing a flattened portion in the waveform. Spectral analysis indicates that the synchronous component is generally attenuated as a result of rubbing-introduced-friction. It is also indicated that light rubbing induced vibrations are characterized by harmonics at frequencies equal to 1x rev., 2x rev., and 3x rev. Whereas, severe rubbing is identified experimentally by a spectrum containing subharmonics at 1/3 and 2/3 of the rotational frequency. Because of the stiffening effect of rubbing on the rotor, the resonance frequency increases. In general, the analytical results show good agreement with experimental data.