Background: It has been proposed that PET alone or combined with CT imaging improves detection of extra-hepatic disease in colorectal cancer liver metastasis (CRCLM). The objective of this study was to determine whether PET/PET-CT has a role in the preoperative workup of patients with potentially resectable CRCLM. Methods: From 2000 to April 2017, MEDLINE, EMBASE, and CENTRAL were searched for randomized and non-randomized studies investigating the use of PET and/or PET-CT in CRCLM. Screening and data collection were performed in duplicate. The primary outcome was overall survival (OS). Secondary outcomes included disease-free survival (DFS), change in surgical management, and futile laparotomy. The quality of the evidence was assessed using GRADE. Random effect models were used to pool treatment effects. Moderate to high heterogeneity was explored via subgroup analyses established a priori. Results: Of 4034 reviewed articles, 22 were included for subsequent analysis. PET/PET-CT did not improve OS (HR 0.94, 95% CI 0.69 – 1.26, I² = 0%) or DFS (HR 1.01, 95% CI 0.82 – 1.26, I² = 0%) when used preoperatively to determine surgical candidacy. In subgroup analyses, PET/PET-CT changed surgical management in 8% of cases (95% CI 5 – 11%, I²= 0), and did not reduce futile laparotomies (RR 0.59, 95% CI 0.24 – 1.47, I²= 47%) in randomized studies. In contrast, PET/PET-CT changed surgical management in 20% of cases (95% CI 17 – 22%, I² = 0) and resulted in fewer futile laparotomies (OR 0.51, 95% CI 0.32 – 0.81, I² = 0%) in non-randomized studies. Conclusions: The use of pre-operative PET/PET-CT does not improve OS or DFS in CRCLM. In addition, there is moderate to high quality evidence demonstrating it has a minimal impact on planning surgical management, and does not prevent unnecessary surgeries.