Thirty patients were operated upon, with chronic implantation of self-stimulating devices for stimulation of the posterior periventricular gray matter for pain control. Three patients required removal of the electrodes because of failure of adequate pain control during the period of percutaneous testing, and five patients report on long term follow-up that they have had no pain relief with stimulation, and have discontinued it. Four patients describe minor relief of pain, and 18 patients report significant relief of pain with stimulation. Therefore, 18 patients, or 66% of the 27 patients having implantation, are considered to have had successful operations, and 12 of the patients are considered failures. Stimulation for brief periods of time, such as 5 to 30 minutes every 2 to 12 hours has been found adequate for control of chronic pain with minimal side effects and a low complication rate.