Background: Although the impact of postoperative complications, especially infectious complications (IC), on long-term survival after transthoracic esophagectomy remains controversial to date, we hypothesized that postoperative IC may affect tumor recurrence and survival of the patients (pts) undergoing transthoracic esophagectomy. Methods: The data from JCOG9907 (Ando N; Ann Surg Oncol 2012) was used to estimate the influence of IC on the outcome of current standard preoperative chemotherapy followed by surgery for clinical stage II/III squamous cell carcinoma of the thoracic esophagus. IC were classified into three: pneumonia, anastomotic leakage, and the others. OS and PFS were estimated by landmark method at 6 months from randomization. Univariate and multivariate analyses using Cox proportional hazard model were performed to assess the impact of postoperative complications on the survival after right-transthoracic esophagectomy with extended lymphadenectomy. Results: Among the 152 analyzed pts, the incidence of overall IC was 36%, among which pneumonia and anastomotic leakage were observed both in 14%. OS of pts with any IC (n=54) was shorter than that of pts without IC (HR 1.66, 95%CI [1.02-2.71]) and PFS also tended to be shorter in pts with any IC (HR 1.44, [0.92-2.23]). OS of pts with pneumonia (n=22) was shorter than that of pts without pneumonia (HR 1.82, [1.01-3.29]), and PFS also tended to be shorter in pts with pneumonia (HR 1.50, [0.85-2.62]). OS of pts with anastomotic leakage (n=21) were nearly identical to that for pts without leakage (HR 1.06, [0.52-2.13]) and PFS was slightly shorter in pts with leakage (HR 1.28, [0.71-2.32]). Multivariate analysis revealed that pneumonia tended to compromise OS and PFS (HR 1.66, [0.87-3.17] and HR 1.37, [0.75-2.51]). Conclusions: This study reveals that postoperative morbidity, especially pneumonia may deteriorate the survival of pts undergoing esophagectomy after preoperative chemotherapy. Achieving esophagectomy without postoperative complications might prolong OS and PFS. Clinical trial information: NCT00190554