Introduction: Between 20 and 40% of liver metastases from colorectal tumor are synchronous. Three types of surgical approaches are proposed; two of them propose a deferred resection and the other, simultaneous resection. The aim of this analysis is to assess the short-and long-term outcomes of simultaneous resections. Method: 212 synchronous liver metastases resected in two centers were evaluated. Comparison between those resected simultaneously with those that were in a deferred way was made. Demographics, liver resections and metastatic characteristics were evaluated. Morbidity and mortality of both alternatives are also evaluated. Results: 63 patients were resected simultaneously with the primary tumor, there were no significant differences in demographic characteristics. There was a greater number of major resections (p = 0.005) in the deferred group. Morbidity and mortality were comparable in both groups. Liver failure (p = 0.037) was higher in the deferred group. Morbidity was 33.2% in the deferred and 10.1% for the simultaneous (p = 0.256). Mortality rate was 2.83% in the deferred and 0.94% in the simultaneous group (p = 0.508). Conclusion: Short and long-term outcomes for both groups are similar. A question remains to be answered: the need of a major hepatectomy will favor the election of a deferred treatment?