Although comorbid panic disorder is associated with more severe symptoms and poorer therapeutic response in depressive patients, the relationship between panic disorder and risk of suicide attempt has not been confirmed. This study aimed to examine the relationship between comorbid panic disorder and clinical characteristics associated with suicidal risk as well as the likelihood of suicide attempt.A total of 223 outpatients with current major depressive disorder participated in the study. Both subjects with panic disorder (33%) and those without panic disorder (67%) were compared based on history of suicide attempts, current psychopathologies, and traits of impulsivity and anger.Subjects with panic disorder had higher levels of impulsivity, depression, and hopelessness and were more likely to report a history of suicide attempts. Subjects with panic disorder were younger at the time of first suicide attempt than those without panic disorder. Logistic regression analyses indicated that comorbid panic disorder was significantly associated with a history of suicide attempts after adjusting for other clinical correlates (odds ratio = 2.8; p < 0.01).These findings suggest that comorbid panic disorder in patients with major depressive disorder may be associated with a more severe burden of illness and may independently increase the likelihood of suicide attempt.