Autonomic dysfunction may contribute to the hemodynamic disturbances in cirrhosis. Tests of autonomic function were performed in 20 patients with cirrhosis and 20 healthy subjects. The patients with severe cirrhosis (Child's grade B or C) had significant reductions in the Valsalva ratio, the heart rate variation during both facial immersion in water and deep breathing, the pressor response to forearm isometric exercise, and the heart rate response to dynamic exercise. The cold pressor test and the heart rate response to lying down were unaffected. These results indicate impairment of both sympathetic and parasympathetic reflexes in severe cirrhosis which may contribute to the hemodynamic disturbances of cirrhosis. Further studies are required to define the site of these defects.