When we look at our hand we immediately know that it is part of our own body. This feeling of ownership of our limbs is a fundamental aspect of self-consciousness. We have studied the neuronal counterparts of this experience. A perceptual illusion was used to manipulate feelings of ownership of a rubber hand presented visually in front of healthy subjects ('rubber hand illusion) while brain activity was measured using functional magnetic resonance imaging (fMRI). The neural activity in the premotor cortex reflected the feeling of ownership of the seen hand. In a second fMRI experiment we demonstrate that the premotor activity does not simply reflect the dominant role of vision or a visual representation. We manipulated the feeling of ownership of a rubber hand which the blindfolded participants were touching. The activity in the premotor cortices reflected the feeling ownership also in this somatic rubber hand illusion. Finally we provide objective neurophysiological evidence that the rubber hand is genuinely incorporated into the body self. We show that the presentation of a painful stimulus (a needle) near the rubber hand elicits cortical activity related to anxiety, but only during the illusion of ownership. In summary, our results suggest that multisensory integration in the premotor cortex is the mechanism for the feeling of body ownership.