Objectives : The purpose of this pilot study was to investigate the potential clinical benefits a single group session of cognitive behavioral therapy in the treatment of patients with panic disorder. Methods : The study participants were 18 patients (14 males, 4 females; mean age=38.9 years), all of whom were assessed as meeting the DSM-IV-TR criteria for panic disorder. All participants attended one two-hour session of structured group cognitive behavioral therapy (CBT). Clinical symptoms was assessed before and eight weeks after the single therapy session using the Panic Disorder Severity Scale (PDSS). Results : Eight weeks after a single session of group CBT significant improvements were found in panic attack frequency, distress during panic attacks, severity of anticipatory anxiety, agoraphobic fear/avoidance, panic-related sensation fear/avoidance, impairment in work functioning, impairment in social functioning. Conclusions : One session of group CBT appears to be an effective treatment of panic disorder by reducing the severity of all symptoms assessed on the PDSS. An attempt should be made to replicate the findings of this pilot study in a larger and controlled, comparative clinical trial.