There are strong evidences involving the abnormalities of basal ganglia and motor control in patients with obsessive-compulsive disorders (OCD). Movement-related potentials (MRP) reflect the activity of sensorimotor cortex and subcortical structures associated with movement preparation. Our aim was to investigate the MRPs in patients with OCD. We recorded MRPs from 20 patients with OCD. MRPs were obtained during simple (self-paced movement of right index finger) and more complex (simultanous movement of both index fingers) motor tasks. Early (N500 and N650) and late components (N1) of MRPs were analysed. Additionally, the onset latency of negativity (N0) was analysed. The results were compared with the data obtained from 14 healthy controls. The amplitudes of N500 and N650 were lower in patients with OCD than those obtained from controls but this difference did not reach statistical significance. Our findings show that MRPs preceding finger movement have failed in demonstration of alteration in cortical movement preparation in patients with OCD. MRPs can be analysed in further studies by using different motor tasks in patients with OCD.