Laparoscopic surgery is one of the treatment modalities available to urologists, who must be familiar with the concepts of the physiology of CO2 and its clinical consequences. CO2 is absorbed during insufflation, leading to hypercapnia, reaching a steady-state from the 20th minute. The insufflation pressure must be between 10 and 14 mmHg. Intraoperative surveillance is based on oxygen saturation (pulse oximeter) and capnography, which measures the CO2 concentration of expired air. The causes of hypercapnia must be prevented: untimely recovery, retroperitoneal dissection, excessive intra-abdominal pressure. If hypercapnia occurs, the patient must be exsufflated and the operation should be resumed after a certain interval. The specific complications of laparoscopy (gas embolism, arrhythmias, pneumothorax) can be avoided by respecting the rules of security and by maintaining surveillance during recovery. The pain due to diaphragmatic peritoneal irritation can also be decreased by complete exsufflation.