OBJECTIVES: Panitumumab is the first fully human anti-EGFR monoclonal antibody to be approved as monotherapy for patients with wild type (wt) KRAS mCRC after failure of fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens. This novel treatment approach is the beginning of a new era of personalised treatment whereby KRAS status is evaluated and only patients who are likely to respond (wt KRAS) receive treatment. The objective of this study was to evaluate the overall budget impact (BI) of the use of panitumumab versus testing KRAS and treating patients with wt KRAS in Greece. METHODS: To consider overall costs associated with panitumumab treatment versus testing KRAS status and treating only wt KRAS patients with panitumumab, a decision analytic model was developed to evaluate BI. Primary drug costs, concomitant medications, infusion costs, radiation therapy, clinic visits, and hospitalisations were included in treatment costs. An expert panel was employed to map mCRC patient flow as a local cancer registry was not available. In this analysis, cost calculations for the public and private sectors were conducted separately. RESULTS: Out of 470 potentially eligible patients for panitumumab monotherapy, the decision analytic model targets 268 (57%) patients with wt KRAS, according to indication. Potential total cost of receiving panitumumab without taking KRAS status into consideration was €8.4million in the public sector, while total cost including KRAS testing to all patients but treating only the wt KRAS patients with panitumumab was €4.9million, resulting in 41.7% savings. Total cost figures for the private sector were €8.7million and €5million respectively, resulting in 42.5% savings. CONCLUSIONS: By identifying the wt KRAS patients who are most likely to respond to treatment, panitumumab improves treatment outcomes and reduces unnecessary exposure to therapy, resulting in overall budget savings. Patient-level clinical benefits derived by panitumumab may lead to improvements in health outcomes and rational allocation of healthcare resources in Greece.