Objective To investigate the cost-effectiveness of panitumumab plus mFOLFOX6 (oxaliplatin, 5-fluorouracil and leucovorin) compared with bevacizumab plus mFOLFOX6 in first-line treatment of patients with wild-type RAS metastatic colorectal cancer (mCRC). Design A semi-Markov model was constructed from a French health collective perspective, with health states related to first-line treatment (progression-free), disease progression with and without subsequent active treatment, resection of metastases, disease-free after successful resection and death. Methods Parametric survival analyses of patient-level progression-free and overall survival data from the only head-to-head clinical trial of panitumumab and bevacizumab (PEAK) were performed to estimate transitions to disease progression and death. Additional data from PEAK informed the amount of each drug consumed, duration of therapy, subsequent therapy use, and toxicities related to mCRC treatment. Literature and French public data sources were used to estimate unit costs associated with treatment and duration of subsequent active therapies. Utility weights were calculated from patient-level data from panitumumab trials in the first-, second- and third-line settings. A life-time perspective was applied. Scenario, one-way, and probabilistic sensitivity analyses were performed. Results Based on a head-to-head clinical trial that demonstrates better efficacy outcomes for patients with wild-type RAS mCRC who receive panitumumab plus mFOLFOX6 versus bevacizumab plus mFOLFOX6, the incremental cost per life-year gained was estimated to be €26,918, and the incremental cost per quality-adjusted life year (QALY) gained was estimated to be €36,577. Sensitivity analyses indicate the model is robust to alternative parameters and assumptions. Conclusions The incremental cost per QALY gained indicates that panitumumab plus mFOLFOX6 represents good value for money in comparison to bevacizumab plus mFOLFOX6 and, with a willingness-to-pay ranging from €40,000 to €60,000, can be considered cost-effective in first-line treatment of patients with wild-type RAS mCRC.