The aim of this study was to determine the relationship between nocturnal panic attacks and comorbidities, clinical variables and panic attack symptoms. One hundred and six consecutive patients with DSM-IV panic disorder were enrolled in the study. The patients were divided into two groups depending on the presence of nocturnal panic attacks. Comorbidities were diagnosed with the help of SCID-I and SCID-II. The groups were compared using the Beck Depression Inventory, State-Trait Anxiety Inventory and Symptom Checklist. Nocturnal panic attacks were not related to comorbidities or age at the onset of the disease. The scores from the Beck Depression Inventory, general scores from the Symptom Checklist, somatization, obsession-compulsion, interpersonal sensitivity and anger-hostility sub-scale scores were higher in the nocturnal panic attack group. Patients with nocturnal panic attacks experience more frequent respiratory symptoms, suggesting that nocturnal panic attacks may be related to respiratory symptoms. Our findings demonstrate that patients with nocturnal panic attacks have more respiratory symptoms of panic, depressive and other psychiatric symptoms than the no nocturnal panic group.