Objective To assess whether preoperative incentive spirometer training would influence the development of postoperative pulmonary complications after lung resection. Methods Sixty-two lung resection patients were prospectively investigated; 17 were given an incentive spirometer preoperatively and 45 did not have an incentive spirometer preoperatively. Postoperatively, both arms exercised with an incentive spirometer. The number of repetitions per day, balls raised per repetition, correct technique of exercising, and postoperative pulmonary complications were compared between the 2 groups. Univariate binary logistic regression analysis of potential predictors of postoperative pulmonary complications led to multivariate analysis of independent predictors. Receiver operating characteristic analysis established the cutoff points of predictors. Results The group with no preoperative incentive spirometer developed more postoperative pulmonary complications than the preoperative incentive spirometer group (24.4% vs. 5.9%, respectively, p = 0.045). The preoperative incentive spirometer arm achieved more repetitions per day, balls per repetition, and correct incentive spirometer technique ( p = 0.002, p < 0.001, p = 0.034, respectively). Balls raised per repetition and repetitions per day postoperatively were identified as independent predictors of postoperative pulmonary complications ( p = 0.032 and p = 0.021, respectively). Less than 5 repetitions per day (sensitivity 93%, specificity 77%, p < 0.001) and less than 2 balls per repetition (sensitivity 93%, specificity 77%, p < 0.001) were predictive of postoperative pulmonary complications. Conclusion Preoperative incentive spirometer exposure ensured better compliance with postoperative treatment and a more accurate technique (balls raised per repetition, repetitions per day). These variables correlated with a lower postoperative pulmonary complication rate.