Background About 20% of patients with colorectal cancer have liver metastases at the time of diagnosis, and surgical resection offers a chance for cure. The aim of the present study was to compare outcomes for patients that underwent simultaneous resection to those that underwent a staged procedure with the bowel-first (classical) strategy by using information from two national registries in Sweden. Methods In this prospectively registered cohort study, we analyzed clinical, pathological, and survival outcomes for patients operated in the period 2008-2015 and compared the two strategies. Results In total, 537 patients constituted the study cohort, where 160 were treated with the simultaneous strategy and 377 with the classical strategy. Patients managed with the simultaneous strategy had less often rectal primary tumors (22% vs. 31%, p = 0.046) and underwent to a lesser extent a major liver resection (16% vs. 41%, p amp;lt; 0.001), but had a shorter total length of stay (11 vs. 15 days, p amp;lt; 0.001) and more complications (52% vs. 36%, p amp;lt; 0.001). No significant 5-year overall survival (p = 0.110) difference was detected. Twenty-five patients had a major liver resection in the simultaneous strategy group and 155 in the classical strategy group without difference in 5-year overall survival (p = 0.198). Conclusion Simultaneous resection of the colorectal primary cancer and liver metastases can possibly have more complications, with no difference in overall survival compared to the classical strategy.