The frequency of common headache instigators or "triggers" and the use of specific behavioral responses to headache episodes were determined using the self-reports of patients with migraine, tension-type, and combined migraine and tension-type headache. Headache diagnostic groups were compared on the nature of headache triggers identified. The diagnostic groups were also compared on the frequency with which they engaged in a set of behavioral responses during headache episodes. No diagnostic group differences were found in triggering stimuli. Emotional, dietary, physical, environmental, and hormonal factors were all reported to be equally likely to precipitate a headache episode regardless of headache diagnosis. There were, however, differences in specific behavioral responses to headache episodes depending upon headache diagnosis. Discriminant analyses were performed to determine the best predictors of headache diagnoses. Migraine patients were significantly more likely to avoid noise, light, social activity, and physical activity compared with tension-type and combined headache patients. When average headache severity was taken into account, the diagnostic group differences in coping responses disappeared. It is concluded from the results of this study that headache severity has a greater impact on coping response than does specific headache diagnosis.