The aim of this study was to evaluate the effect of dietician-delivered intensive nutritional support (INS) on postoperative outcome in patients with esophageal cancer. Approximately 50–80% of patients with esophageal cancer are malnourished at the time of diagnosis. Malnutrition enhances the risk of postoperative complications, resulting in delay of postoperative recovery and impairment of quality of life. Sixty-five patients with esophageal cancer were included. All patients who received surgery (n = 28) in the time frame between March 2009 and April 2010, the first year after the start of INS, were included in the INS intervention group. The control group (n = 37) consisted of patients who received surgery during the 3 years before the start of INS. Logistic regression analysis was used to compare differences in severity of postoperative complications using the Dindo classification. Linear regression was applied to evaluate differences in preoperative weight change. The adjusted odds ratio for developing serious complications after surgery of INS compared with the control group was 0.23 (95% confidence interval: 0.053–0.97; P = 0.045). Benefit was mainly observed in patients who received neoadjuvant therapy before esophagectomy (n = 35). The INS program furthermore resulted in a relative preoperative weight gain in comparison with the control group of +4.8% (P = 0.009, adjusted) in these neoadjuvant-treated patients. This study shows that dietician-delivered INS preserves preoperative weight and decreases severe postoperative complications in patients with esophageal cancer.