Background: Pneumonia after pulmonary resection occurs in 5% to 12% of patients and causes substantial morbidity. Oral hygiene regimens lower the incidence of ventilator-associated pneumonias; however, the impact in patients undergoing elective pulmonary resection is unknown. We conducted a prospective pilot study to assess the feasibility of an oral hygiene intervention in this patient cohort. Methods: Patients undergoing elective pulmonary resection were prospectively enrolled in a single-arm interventional study with time-matched controls. Participants were asked to brush their teeth with 0.12% chlorhexidine three times daily for 5 days before their operations and 5 days or until the time of discharge after their operations. Patients were eligible if they had known or suspected lung cancer and were undergoing (1) any anatomic lung resection or (2) a wedge resection with forced expiratory volume in 1 second or diffusing capacity of lung for carbon monoxide less than 50% predicted. Results: Sixty-two patients were enrolled in the pilot intervention group and compared with a contemporaneous cohort of 611 patients who met surgical inclusion criteria. Preoperative adherence to the chlorhexidine toothbrushing regimen was high: median 100% (interquartile range: 87% to 100%). Postoperatively, 80% of patients continued toothbrushing, whereas 20% declined further participation. Among those who participated postoperatively, median adherence was 86% (interquartile range: 53% to 100%). There was a trend toward reduction in postoperative pneumonia: 1.6% (1 of 62) in the intervention cohort versus 4.9% (30 of 611) in the time-matched cohort (p = 0.35). The number needed to treat to prevent one case of pneumonia was 30 patients. Conclusions: This pilot study demonstrated patients can comply with an inexpensive perioperative oral hygiene regimen that may be promising for reducing morbidity (Clinical Trials Registry: NCT01446874).