BACKGROUND: Fentanyl-induced cough (FIC) has a reported incidence of 13–65% on induction of anesthesia. Incentive spirometry (IS) creates forceful inspiration, while stretching pulmonary receptors. We postulated that spirometry just before the fentanyl (F) bolus would decrease the incidence and severity of FIC. METHODS: This study enrolled 200 patients aged 18–60 years and with American Society of Anesthesiologists status I or II. The patients were allocated to two groups of 100 patients each depending on whether they received preoperative incentive spirometry before fentanyl administration. Patients in the F+IS group performed incentive spirometry 10 times just before an intravenous bolus of 3 µg/kg fentanyl in the operating room. The onset time and number of coughs after fentanyl injection were recorded as primary outcomes. Any significant changes in blood pressure, heart rate, or adverse effects of the drug were recorded as secondary outcomes. RESULTS: Patients in the F+IS group had a significantly lower incidence of FIC than in the F group (6% vs. 26%) (P < 0.05). The severity of cough in the F+IS group was also significantly lower than that in group F (mild, 5 vs. 17; moderate 1 vs. 7; severe, 0 vs. 2) (P < 0.05). The median onset time was comparable in both groups (9 s [range: 6–12 s] in both groups). CONCLUSIONS: Preoperative incentive spirometry significantly reduces the incidence and severity of FIC when performed just before fentanyl administration.