To investigate the involvement of the autonomic nervous system in Cluster Headache (CH) patients, we compared the cardiovascular reflex responses in a group of CH subjects and a group of controls. We considered five tests: 1) deep breathing test (DB); 2) lying to standing test; 3) heart rate response to Valsalva manoeuvre; 4) blood pressure response to standing; 5) blood pressure response to sustained handgrip. Our data confirm an autonomic dysfunction in CH, particularly regarding the parasympathetic system. Alternative interpretations of these results are discussed.