OBJECTIVES: Bevacizumab, known as VEGF inhibitor, has demonstrated significant activity when it is used with cytotoxic chemotherapy together in metastatic colorectal cancer(mCRC). However, bevacizumab is an expensive medication known as not cost-effectiveness with high ICER(Incremental Cost-Effectiveness Ratio) in other countries. The purpose of this study was to examine the economic efficiency of treating mCRC with bevacizumab plus chemotherapy versus chemotherapy alone from the perspective of the social aspects in Korea. METHODS: Markov model was developed to compare the cost and benefits of adding bevacizumab to oxaliplatin plus FU/LV(FOLFOX) or capecitabine plus FU/LV(CapeOX) with FOLFOX or CapeOX alone. We searched clinical documentation, extracted median time to progression and median overall survival from each chemotherapy, and calculated the transition probability and death rate per cycle. Model simulates costs and outcomes in hypothetical cohort of metastatic colorectal cancer for 5 years with 5% discount rate. We included that direct and non-direct medical cost(2009). The ICERs were calculated from incremental life-years gained(LYG) and incremental costs between single and combination therapy. Sensitivity analyses were performed on crucial parameters. RESULTS: After markov model simulation for 5 years, FOLFOX+bevacizumab gained 1.58 years/patient and FOLFOX 1.42 years/patient, whereas CapeOX+bevacizumab 1.57 years/patient and CapeOX 1.31 years/patient. Total cost of FOLFOX+bevacizumab, FOLFOX, CapeOX+bevacizumab, CapeOX are ₩88,567,199($70,854), ₩73,938,752($59,151), ₩91,904,773($73,524), ₩43,864,530($35,092), respectively. The ICERs of additional bevacizumab when combined with FOLFOX, CapeOX were ₩89,974,151 ($71,979), ₩181,331,641 ($145,065), respectively, per life year gained, proving very high in both case combination therapy. Sensitivity analysis showed that the price of bevacizumab is a key parameter of its cost-effectiveness. CONCLUSIONS: As a result, it is proven that the addition of bevacizumab to FOLFOX, CapeOX in mCRC patients is expensive given clinical benefit in terms of LYG in Korea. This findings may offer one of the useful basic data selecting chemotherapy regimens in treating for mCRC.