Background Laparoscopic surgery for colorectal cancer has been shown in clinical trials to be effective regarding short-term outcomes and oncologically safe. Health economic analyses have been performed early in the learning curve when adoption of laparoscopic surgery was not extensive. This cost-effectiveness analysis evaluates laparoscopic versus open colorectal cancer surgery in Swedish routine care. Methods In this national retrospective cohort study, data were retrieved from the Swedish ColoRectal Cancer Registry. Clinical effectiveness, resource use and unit costs were derived from this and other sources with nationwide coverage. The study period was 2013 and 2014 with 1 year follow-up. Exclusion criterion comprised cT4-tumors. Clinical effectiveness was estimated in a composite endpoint of all-cause resource-consuming events in inpatient care, readmissions and deaths up to 90 days postoperatively. Up to 1 year, events predefined as related to the primary surgery were included. Costs included resource-consuming events, readmissions and sick leave and were estimated for both the society and healthcare. Multivariable regression analyses were used to adjust for differences in baseline characteristics between the groups. Results After exclusion of cT4 tumors, the cohort included 7707 patients who underwent colorectal cancer surgery: 6060 patients in the open surgery group and 1647 patients in the laparoscopic group. The mean adjusted difference in clinical effectiveness between laparoscopic and open colorectal cancer surgery was 0.23 events (95% CI 0.12 to 0.33). Mean adjusted differences in costs (open minus laparoscopic surgery) were $4504 (95% CI 2257 to 6799) and $4480 (95% CI 2739 to 6203) for the societal and the healthcare perspective respectively. In both categories, resource consuming events in inpatient care were the main driver of the results. Conclusion In a national cohort, laparoscopic colorectal cancer surgery was associated with both superior outcomes for clinical effectiveness and cost versus open surgery. Keywords Cost-effectiveness analysis • Laparoscopic surgery • Colorectal cancer Colorectal cancer is the second most common form of cancer in men and third most common cancer in women [1].