Objective : Panic disorders are frequently accompanied by major depressive disorder (MDD). There is insufficient information about which clinical factors in panic disorder are associated with comorbid MDD. The aim of this study is to identify clinical factors related with comorbid MDD in patients with panic disorder. Methods : Two experienced psychiatrists diagnosed panic disorder based on DSM-IV criteria. This diagnosis in the 275 subjects was confirmed again by Mini-International Neuropsychiatric Interview (MINI). Lifetime comorbid psychiatric diagnoses were examined by MINI. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA) and Panic Disorder Severity Scale (PDSS) were used to assess the severity of depressive, anxiety and panic symptoms. Results : The result of MINI showed that 95 patients (34%) with panic disorder satisfied the diagnosis of MDD. Multivariate logistic regression model showed that comorbid generalized anxiety disorder (GAD) and the symptom of "fear of losing control or going crazy" were associated with MDD in patients with panic disorder. In female patients, the "chills or hot flushes" symptom was also associated with comorbid MDD. Conclusion : These results showed that coexisting GAD and certain symptoms of panic are associated with comorbid MDD.