Twenty-eight chronic headache sufferers of three headache types (migraine, tension and combined migraine-tension) selected on the basis of explicit inclusion and exclusion criteria and matched on five demographic characteristics were assessed in a headache and non-headache state on a number of psychophysiological measures (frontalis, forearm and neck EMG; cephalic vasomotor response; hand surface temperature; heart rate and skin resistance level) and a number of stimulus conditions (baseline, self-control, cognitive and physical stressors). Results indicated no significant differences between the three headache groups or headache states on any measure during baseline condition. Analyses of post-stress adaptation periods led to the area of most significant differences, with a number of findings lending support for Sternbach's inadequate homeostatic responding hypothesis of migraine, but not tension, headache. No support was found for the sustained levels of muscle tension hypothesis of the etiology of tension headache. Implications for the etiology and treatment of headache are discussed.