AIM: The purpose of this study is to determine the anatomica! aspects, mechanisms, risk factors and appropriate management of development of pneumothorax during a routine colonoscopy. MATERIAL OF STUDY: The review has been carried out according to PRISMA statement. The literature search included PubMed and Scopus database. The search string was “pneumothorax AND colonscopy”. RESULTS: A total of 36 papers met the inclusion criteria out of 57 non duplicate citations. Papers describing the clinical course of 36 patients with pneumothorax alter colonoscopy plus one case (our personal report), achieving a total of 37 patients available for analysis have been investigated. The review revealed a female predominance. 16 procedures were just diagnostic without biopsies, whereas in 21 cases procedures were performed with interventional maneuvers. The most common clinical feature of extraperitoneal colonic perforation was dyspnea in 31 patients (84%). Treatment included unilateral or bilateral chest drain, chest drain and laparotomy, only laparotomy or laparoscopìc approach, endoscopic treatment and conservative management was also reported. DISCUSSION: Rarely, colonic perforation during colonoscopy can occur into the extraperitoneal space, thus leading to the passage and diffusion of air along the fasciai planes and large vessels, possibly causing pneumoretroperitoneum, pneumomediastinum, pneumopericardium, pneumothorax, and subcutaneous emphysema. The combination of intraperitoneal and extraperitoneal perforation has also been reported. CONCLUSION: Pneumothorax and tension pneumothorax following a colonoscopy is an extremely rare but severe and often lifethreatening complication. If the patient develops dyspnea and pneumoderma during or alter this procedure, a chest radiogram or thoracoabdominal CT should be taken for diagnostic purposes. Urgent treatment, starting with chest tube insertion(s) and laparotomy or laparoscopy could be lifesaving.