PURPOSE: High preoperative hemoglobin A1c (HbA1c) levels have been suggested to increase complications after esophagectomy. Minimally invasive esophagectomy (MIE) is less invasive than open esophagectomy (OE) and may reduce postoperative complications. However, it has not been established whether MIE contributes to low morbidity in patients with high preoperative HbA1c levels. Thus, the current study aimed to elucidate the effect of preoperative HbA1c levels on the incidence of complications each after OE and MIE. METHODS: A total of 280 patients who underwent OE and 304 patients who underwent MIE for esophageal cancer between April 2005 and April 2020 were retrospectively analyzed. The OE and MIE groups were further divided into two groups according to their preoperative HbA1c levels (< 6.9%, ≥ 6.9%). RESULTS: Patients with high HbA1c levels had a significantly higher incidence of surgical site infections (SSIs) after OE (P = 0.0048). Multivariate analysis demonstrated that a high HbA1c level was an independent risk factor for frequent SSIs after OE (hazard ratio 2.52; 95% confidence interval, 1.101- 5.739; P = 0.029). On the contrary, a high HbA1c level did not affect the incidence of SSI after MIE (P = 1.00). A high HbA1c level was not associated with the incidence of morbidities other than SSI after OE and MIE. CONCLUSIONS: A high preoperative HbA1c level significantly increased SSI risk after OE but not after MIE. It was suggested that lower invasiveness of MIE could contribute to a low incidence of SSI, even in patients with poor preoperative glycemic control.