Contralateral intraoperative tension pneumothorax is a rare complication of thoracic surgical procedures. Here we present three cases of tension pneumothorax that developed during single-lung transplantation for emphysema and pulmonary fibrosis. To the best of our knowledge, this is only the second report of contralateral intraoperative tension pneumothorax during single-lung transplantation. A high index of clinical suspicion is required for the detection of this potentially catastrophic complication.