An attempt was made to differentially diagnose panic disorder with agoraphobia from social phobia on the basis of self-reported phobic situations, panic attack symptomatology, and feared outcomes. Sixty-nine patients with panic disorder (with and without agoraphobia) were compared with 69 patients with social phobia. Subjects completed a modified self-report version of the panic and phobia sections from the Composite International Diagnostic Interview to assess phobic situations, panic symptomatology, and feared outcomes. The two groups were distinguishable on all three measures. A diagnostic algorithm was developed that predicted the primary diagnosis allocated by a clinician for subjects who meet DSM-III-R criteria for panic disorder (with or without agoraphobia) rather than social phobia on the basis of self-reported phobic avoidance, panic symptomatology, and feared outcomes.