BACKGROUND: Few studies identifying variables associated with prognosis after resection of colorectal liver metastases (CLM) account for treatment with multiagent chemotherapy (fluoropyrmidines with irinotecan, oxaliplatin, bevacizumab, and/or cetuximab). The objective of this retrospective study was to determine the effect of multiagent chemotherapy on long-term survival after resection of CLM. METHODS: Demographics, clinicopathologic tumor characteristics, treatments, and long-term outcomes were reviewed. RESULTS: From 1996 to 2006, 230 patients underwent resection of CLM. Treatment strategies before and after resection included fluoropyrimidine monotherapy (n = 34 and n = 39), multiagent chemotherapy (n = 81 and n = 73), and observation (n = 115 and n = 118). Prehepatectomy treatment strategy was not associated with overall survival. Actuarial 4-year survival was 63%, 39%, and 40% for patients treated with multiagent chemotherapy, fluoropyrimidine monotherapy, and observation after hepatectomy, p = 0.06. Posthepatectomy multiagent chemotherapy (p = 0.04, HR 0.52 [0.27-1.03]), duration of posthepatectomy chemotherapy treatment of 2 months or longer (p = 0.05, HR 0.49 [0.25-0.99]), carcino-embryonic antigen level >10 ng/mL (p = 0.03, HR 2.09, 95% CI [1.32-3.32]), and node positive primary tumor (p = 0.002, HR 1.79 [1.06-3.02]) were associated with overall survival in multivariate analysis. CONCLUSIONS: The association of posthepatectomy multiagent chemotherapy with overall survival in this retrospective study indicates the need for prospective randomized trials comparing multiagent chemotherapy and fluoropyrimidine monotherapy for CLM.