['Postoperative hyperglycemia is associated with infectious complications after various types of surgery. Our objective was to determine whether postoperative blood glucose levels up to 1\xa0week after highly invasive esophageal cancer surgery are associated with the incidence of postoperative infections (POIs).', 'We conducted a retrospective chart review of 109 consecutive thoracic esophageal squamous cell cancer patients who underwent invasive esophagectomy with thoracotomy and laparotomy. The incidence of postoperative POIs and risk factors for POIs, including postoperative blood glucose levels, were evaluated.', 'Of the 109 patients, 37 (34.0\xa0%) developed POIs. Clinically, 73.0\xa0% of the POIs became evident on or after postoperative day 4 (median, 5.25\xa0days; interquartile range, 3.00-9.25\xa0days). On and after postoperative day 3, chronological changes in blood glucose levels were significantly different between two groups of patients with or without POIs, as indicated by repeated measures ANOVA (P\u2009=\u20090.006). Multivariate logistic regression analysis results showed that an increased blood glucose concentration on postoperative day 3 was a significant risk factor for POIs.'] Is hyperglycemia 3 days after esophageal cancer surgery associated with an increased risk of postoperative infection?