Preoperative risk assessment for postoperative pulmonary complications is essential when counseling patients about the risks of surgery because of their significant associated morbidity and mortality. There are many patient-related, operation-related, and anesthesia-related risk factors for the development of PPCs. Though many of these risk factors are not modifiable, they can be useful in evaluating preoperative risk, especially when combined into formal risk indices. Preoperative risk assessment enables clinicians to target preoperative testing and perioperative risk reduction strategies to high-risk patients. Reducing PPC risk at the patient level will require a greater understanding of the impact of modifying risk factors through interventional trials. Reducing hospital PPC rates will require future research into the processes of care associated with PPCs through controlled observational and interventional trials.