Background The optimal management of colorectal cancer with synchronous liver metastases has not yet been elucidated. The aim of the present study was systematically to review current evidence concerning the timing and sequence of surgical interventions: colon first, liver first or simultaneous. Methods A systematic literature review was performed of clinical studies comparing the timing and sequence of surgical interventions in patients with synchronous liver metastases. Retrospective studies were included but case reports and small case series were excluded. Preoperative and intraoperative data, length of hospital stay, perioperative mortality and morbidity, and 1-, 3- and 5-year survival rates were compared. The studies were evaluated according to a modification of the methodological index for non-randomized studies (MINORS) criteria. Results Eighteen papers were included and 21 entries analysed. Five entries favoured the simultaneous approach regarding duration of procedure, whereas three showed no difference; five entries favoured simultaneous treatment in terms of blood loss, whereas in four there was no difference; and all studies comparing length of hospital stay favoured the simultaneous approach. Five studies favoured the simultaneous approach in terms of morbidity and eight found no difference, and no study demonstrated a difference in perioperative mortality. One study suggested a better 5-year survival rate after staged procedures, and another suggested worse 1-year but better 3- and 5-year survival rates following the simultaneous approach. The median MINORS score was 10, with incomplete follow-up and outcome reporting accounting primarily for low scores. Conclusion None of the three surgical strategies for synchronous colorectal liver metastases appeared inferior to the others. Liver first, simultaneous or last? © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.