Postoperative pulmonary complications (PPC) account for a substantial portion of the risks related to surgery and anesthesia and are a source of postoperative morbidity, mortality and longer hospital stays. The current basis for our understanding of the nature of PPC is weak; only a small number of high-quality studies are available, a uniform definition has not emerged, and studies have focused on specific patients and kinds of surgeries. Current evidence suggests that risk factors for PPC are related to the patient's health status and the particular anesthetic and surgical procedures chosen. Age, general co-morbidity, pre-existing respiratory and cardiac diseases, the use of general anesthesia and the overall surgical insult. are the most significant factors associated with complications. Election of anesthetic technique, postoperative analgesia and physical therapy seem to be the preventive measures that are best supported by evidence.