Intrinsic optical signals to electrical stimulation of the face and hand were recorded from the human primary sensory cortex. Somatotopic representation of optical recording was compared with that of MEG. The recordings were carried out on 10 patients bearing tumors, adjacent to the sensorimotor cortex. The cortical surface was illuminated with voltage-stabilized Xe white light. The reflected light passed through a band-pass filter (605 nm), and eight functional images were acquired during 5 s using the intrinsic optical imaging system (Imager 2001). The median nerve, the first and the fifth digits or the first and the third branches of the trigeminal nerve were electrically stimulated. In all patients, the somatosensory optical signals were recorded on the primary sensory cortex. The location of the optical signals corresponded with that of the dipole estimation of the cortical sensory responses in MEG. The optical signals to the stimulation of the first and the fifth digits, and the first and the third branches of the trigeminal nerve were recorded on different locations among the sensory strip. These results indicated that the intrinsic optical signal recorded from the human primary sensory cortex represented somatotopic representation well, and could be a useful technique in monitoring human cortical neuronal activity.