There have been some recent reports proposing that muscle contraction headache (MCH) and migraine are similar and may have a common etiology. It has been hypothesized that derangement of the autonomic nervous system (ANS) plays an important role in the pathogenesis of migraine. However, reports on the ANS function in MCH have rarely been submitted. Therefore, in this report, MCH patients were investigated as well as migraine patients. The cardiovascular reflex responses by orthostatic test, isometric work test and the pulse rate (R-R interval) variation in fifteen MCH patients and fifteen migraine patients were recorded during headache-free intervals. The plasma norepinephrine (NE) levels were also measured throughout the orthostatic tests. Fifteen healthy subjects served as the age-matched control group. In the MCH group and the migraine group, blood pressure immediately after going from the supine to the erect position decreased more significantly than in the control group. The basal NE level was significantly low in both the MCH group and the migraine group, in comparison with the control group. MCH patients as well as migraine patients showed cardiovascular sympathetic hypofunction.