We present a novel silicon-organic hybrid modulator based on an single waveguide interferometer, which can be used for optical communications. A prototype modulator showing a voltage dependent transmission spectrum is obtained by cladding a dual-mode waveguide in a 250 nm silicon-on-insulator technology with a customized organic electro-optic layer. The presented prototype is to the best of the authors’ knowledge the first integrated single waveguide silicon-organic hybrid modulator.