The results of analytical and experimental investigations for an electro-optic polarization controller are reported. A device configuration composed of two polarization converters with a phase shifter centered between them and all integrated over a single Ti diffused channel waveguide on LiNbO 3 is used. Polarization control is achieved by applying voltages on the three integrated elements independently to adjust the phase difference between orthogonal TE and TM components of a guided optical wave as well as their relative strength. Experimental results agree with analytical predictions. For arbitrary incident polarization, endless polarization transformation can be realized at the output.