The major aim of the present study was to investigate whether painful stimuli have a differential effect on the Readiness Potential (RP) in terms of the early and late components. We hypothesized that painful stimuli would modulate the cortical movement preparatory activity and the components to a different extent when compared to non-painful stimuli. The readiness potential (RP), which is a slow negative electrical brain potential that occurs before voluntary movement, can be interpreted as a measure of intrinsic brain activity originating from self-regulating mechanisms. Early and late components of the RP may indicate clinical-neurophysiological features such as motivation, preparation, intention, and initiation of voluntary movements. 15 healty volunteers were enrolled in this study. We conducted electrical stimulation trials in two randomized blocks termed as “no-pain condition” and “pain condition“. Our results demonstrated that painful stimuli were preceded by an enhanced RP at the Cz channel (p<0.05). The mean amplitude of the RP at the early phase was significantly higher for the painful stimuli when compared to the non-painful stimuli (p<0.05). Our results indicate that electrical painful stimuli, which can be considered as an unpleasant and stressful condition, modulate the motor preparation at sensory motor regions to a different extent when compared to non-painful electrical stimuli. Since early component of the RP represents cortical activation due to anticipation of the stimuli and the allocation of attentional resources, our results suggest that painful stimuli may affect the motor preparation processes and the prediction of the movement at the cortical level.