objectIve. To assess the relationship of clinical data and the results of preoperative pulmonary functional evaluation with postoperative pulmonary complications. Methods. We conducted a retrospective cohort study with patients who underwent pulmonary functional evaluation over a period of 5 years. We analyzed clinical, demographic and spirometric data, surgical procedures performed and postoperative pulmonary complications. results. We analyzed the medical records of 521 patients. Mean age was 59.5 ± 14 years, 65.8% were male, and 93.4% were white. Mean FEV1 was 76.6 ± 24.6% of predicted. There were clinical comorbidities in 73.5% of all cases (COPD in 29.8%). The most common surgical sites were thorax (n = 122; 23.4%) and upper abdomen (n = 117; 22.5%). Postoperative pulmonary complications occurred in 99 patients (19.0%), with respiratory failure being the most common (4.6%). Forty-three (8.3%) patients died. Rates of pulmonary complications were higher after thoracic (28.9%), cardiac (28%) and upper abdomen surgery (24.3%) (p≤0.0001). Most patients (66.7%) with pulmonary complications were classified as ASA III or IV (p<0.01), and in 70.2% of operations, time on anesthesia was > 3.5 hours (p≤0.0001). The difference in median length of hospital stay between patients with and without pulmonary complications was statistically significant (23.5 [15.8-34] days vs. 10 [6-18] days; p<0.001). Patients who had never smoked had fewer complications than those with current or past smoking history (p=0.04). We did not detect significant associations between postoperative pulmonary complications and presence of COPD, FEV1 or body mass index (p>0.05). conclusIon. The most important factors associated with postoperative pulmonary complications were surgical site, time of anesthesia, and ASA classification.