We present in this paper a silicon retina - specific CMOS image sensor – dedicated to movement estimation. This circuit has been fabricated in a standard 0.35μm CMOS process. The pixel is composed with both sensitive elements - a photodiode is used to convert photons to electrons - and electronic components for computations. Its goal is to extract the optical flow from two acquired images. Movement estimation is a very often used task after image acquisition, which usually needs a sensor, a processing unit (DSP, FPGA) and external memories [5]. Here, the functionality is achieved in a single chip, by an electrical way, giving compactness and low power to this costing task. The movement estimation algorithm we use comes from [2], its advantages are: robustness with real sequences, its real use in robotics, and its good electrical mapping. The circuit’s architecture is divided in two parts, corresponding to the two steps of the original algorithm.