Objectives The influence of reoperation on long-term prognosis is unknown. In this large population-based cohort study, it was aimed to investigate the influence of a reoperation within 30 days of oesophageal cancer resection on survival even after excluding the initial postoperative period.

Design This was a nationwide population-based retrospective cohort study.

Setting All hospitals performing oesophageal cancer resections during the study period (1987–2010) in Sweden.

Participants Patients operated for oesophageal cancer with curative intent in 1987–2010.

Primary and secondary outcomes Adjusted HRs of all cause, early and late mortality up to 5 years after reoperation following oesophageal cancer resection.

Results Among 1822 included patients, the 200 (11%) who were reoperated had a 27% increased HR of all-cause mortality (adjusted HR 1.27, 95% CI 1.05 to 1.53) and 28% increased HR of disease-specific mortality (adjusted HR 1.28, 95% CI 1.04 to 1.59), compared to those not reoperated. Reoperation for anastomotic insufficiency in particular was followed by an increased mortality (adjusted HR 1.82, 95% CI 1.19 to 2.76).

Conclusions This large and population-based nationwide cohort study shows that reoperation within 30 days after primary oesophageal resection was associated with increased mortality, even after excluding the initial 3 months after surgery. This finding stresses the need to consider any actions that might prevent complications and reoperation after oesophageal cancer resection.