The case history of a 47 yr old man with spontaneous pain and hyperalgesia following right hemisphere cortical contusion is presented. The patient had a transient hemiparesis and residual hemisensory deficit in all tested modalities. Six mth after injury he began to have pain. An electrode was stereotaxically implanted in his left posterior internal capsule and, intermittently, trains of brief electrical pulses were passed eliciting paraesthesiae in the painful areas. Complete relief of pain was produced by this method for more than one yr.