Theoretical mechanisms offered to account for the therapeutic gains observed in migraine patients trained in hand warming via biofeedback techniques have been inconsonant and lack a sufficient data base. The effects of directional skin temperature self-regulation upon regional cerebral blood flow (rCBF) were measured in two groups of migraine patients trained either to increase or decrease hand temperature. Following training, serial measurements of rCBF by 133Xe inhalation were made during a steady-state condition and another during skin temperature self-regulation. Both mean hemispheric and regional CBF changes occurred during volitional alteration in skin temperature. Changes tended to differ in direction and/or magnitude, depending upon whether the hands were warmed or cooled. The hypothesis was supported that skin temperature control contributes to rCBF changes which may be responsible for the reduction of migraine symptoms. Comparison of rCBF changes measured in migraineurs and normal volunteers suggested that cerebral vasomotor reactivity was increased in migraineurs.