To determine whether patients with generalized social phobia exhibit evidence of abnormal autonomic nervous system (ANS) functioning, 15 non-depressed, medication-free subjects with DSM-IV social phobia (generalized type) and 15 healthy control subjects participated in a series of autonomic function tests. Generalized social phobics exhibited increased blood pressure responsivity to Valsalva and exaggerated vagal withdrawal in response to isometric exercise, but normal cardiovascular responsivity to all other tasks. Plasma norepinephrine and epinephrine levels were also normal. Studies with larger sample sizes and the use of specific neuropharmacologic probes seem warranted to further delineate a role for autonomic dysfunction in the pathophysiology of this disorder.