Thoracic endometriosis syndrome is a rare disorder characterized by the presence of functioning endometrial tissue in the pleura, the lung parenchyma, or the airways. The diagnosis of thoracic endometriosis syndrome is usually based on the temporal relationship of the patient’s symptoms with menses, and resolution of symptoms with medical treatment for endometriosis. This condition should be suspected in female patients presenting with recurrent hydropneumothoraces. The diagnosis of pleural endometriosis at imaging is feasible even without biopsy confirmation, but requires a high-index of suspicion. We present the clinical presentation and imaging findings of a 31-year-old woman with pleural endometriosis presenting with hydropneumothorax and concomitant pelvic endometriosis, and discuss the radiographic, ultrasound, and computed tomography findings of patients with pleural endometriosis.