We report here a case of reexpansion pulmonary edema following laparoscopy-assisted distal gastrectomy (LADG) for early gastric cancer. A 57-year-old Japanese woman with no preoperative comorbidity was diagnosed with early gastric cancer. The patient underwent LADG using the pneumoperitoneum method. During surgery, the patient was unintentionally subjected to single-lung ventilation for approximately 247 minutes due to intratracheal tube dislocation. One hour after surgery, she developed severe dyspnea and produced a large amount of pink frothy sputum. Chest radiography results showed diffuse ground-glass attenuation and alveolar consolidation in both lungs without cardiomegaly. A diagnosis of pulmonary edema was made, and the patient was immediately intubated and received ventilatory support with high positive end-expiratory pressure. The patient gradually recovered and was weaned from the ventilatory support on the third postoperative day. This case shows that single-lung ventilation may be a risk factor for reexpansion pulmonary edema during laparoscopic surgery with pneumoperitoneum.