Aim Unlike meta-analyses of randomized controlled trials, population-based studies in colorectal cancer (CRC) patients have shown a significant association between open surgery and increased 30- and 90-day mortality compared with laparoscopic surgery. Long-term mortality, however, is scarcely reported. This retrospective population-based study aimed to compare long-term mortality after open and laparoscopic surgery for CRC. Method The Dutch Colorectal Audit and the Dutch Cancer Centre registry were used to identify patients from three large nonacademic teaching hospitals who underwent curative resection for CRC between 2009 and 2018. Patients with relative contraindications for laparoscopic surgery (cT4 or pT4 tumours, distant metastasis requiring additional resection and emergency surgery) were excluded. Multivariable regression was used to assess the effect of laparoscopic surgery on long-term mortality with adjustment for gender, age, American Society of Anesthesiologists score, TNM stage, chemoradiation therapy and other confounders. Results We included 4531 patients, of whom 1298 (29%) underwent open surgery. The median follow-up was 43 months (interquartile range 23-71 months). Open surgery was associated with an increased risk of long-term mortality (adjusted hazard ratio 1.26, 95% confidence interval 1.10-1.45, p = 0.001). Mixed-effects Cox regression with year of surgery as a random effect also showed an increased risk after open surgery (adjusted hazard ratio 1.33, 95% confidence interval 1.11-1.52, p = 0.004). Conclusion Open surgery seems to be associated with increased long-term mortality in the elective setting for CRC patients. A minimally invasive approach might improve long-term outcomes.