Eleven patients with panic disorder or agoraphobia with panic attacks completed an 8-week single-blind trial of trazodone (300 mg/day) without concurrent behavioral instructions. The measures of change included ratings of generalized and panic anxiety, phobias, and depression and a behavioral avoidance test, which were administered during a baseline period of placebo administration and at 4 and 8 weeks of the trial. There was significant improvement on all symptom dimensions, which suggests that trazodone may have specific antipanic and antiphobic actions and underscores the importance of serotonergic mechanisms in these anxiety disorders.