We investigated whether secretory leukocyte protease inhibitor (SLPI) is associated with pulmonary complications after esophagectomy. We measured serial changes in the SLPI concentration in the bronchoalveolar lavage fluid (BALF) of 34 patients who underwent and examined the relationship between SLPI and postoperative morbidity. Fifteen (44%) of 34 patients (high group) had a BALF SLPI concentration >90,000 pg/mL at the end of the surgery (postoperative day [POD] 0). There was no significant difference between the high group and other 19 patients (low group) with respect to age, sex, preoperative comorbid conditions, tumor stage, surgical technique, operating time, or blood loss volume. Days of intubation and pulmonary complication rate were significantly increased in the high group compared with the low group. Logistic regression analysis revealed that the BALF SLPI level on POD 0 was significant for pulmonary complications. Our results indicate that assaying SLPI levels in BALF can be useful for the prediction of pulmonary complications after esophagectomy.