PURPOSE: The aim of this study was to determine the incremental effectiveness (the differences in progression-free survival between treatments), the incremental cost and the incremental cost-effectiveness of Genexol-PM compared to Paclitaxel when these drugs were used as treatment for patients with metastatic breast cancer. METHODS: In the absence of any comparative direct evidence of the relative efficacy of Paclitaxel and Genexol-PM in this setting, a meta-analysis was conducted to determine the effects of the Paclitaxel on the health outcome. The decision tree model was constructed to evaluate the two treatment regimens. All the costs are in 2008 Korean Won (KW) and they were evaluated according to the 3rd party payer perspective, and the direct nonmedical and indirect costs were excluded. RESULTS: When compared with Paclitaxel, Genexol-PM was shown to increase the response rate and the time to progression for patients with metastatic breast cancer. Although the overall treatment costs of Genexol-PM were slightly higher than those of Paclitaxel, Genexol-PM was associated with a delayed time to progression of 4.78 months per patient. The incremental cost effectiveness ratio for Genexol-PM versus Paclitaxel was KW 2,295,228 per year gained, which is far below the per capita GDP or the threshold of the willingness-to-pay in Korea. CONCLUSION: Compared with Paclitaxel, Genexol-PM for treating metastatic breast cancer is within the acceptable range of the cost-effectiveness ratio for medical intervention.