Catamenial pneumothorax (CP) is a special type of pneumothorax occurring in women of reproductive age related with the menstrual cycles. In most cases patients are misdiagnosed as primary spontaneous pneumothorax and are admitted to the hospital with recurrences. CP is mostly associated with thoracic endometriosis. Characteristic lesions of the disease include diaphragmatic perforations and also diaphragmatic or pleural spots or nodules in addition to bullae or blebs. There are a few cases in the literature with partial liver herniation from diaphragmatic defects in patients with catamenial pneumothorax. In this study, we present a 45-year-old female patient with the diagnosis of catamenial pneumothorax and herniation of liver from diaphragmatic defects.