OBJECTIVES: The objective of this study was to estimate Incremental Cost-Effectiveness Ratio (ICER) of utilizing eribulin for Metastatic Breast Cancer (MBC) in Spain for the second line (2L) treatment of HER2 negative (HER2NEG) patients. METHODS: Eribulin is indicated for the treatment of patients with locally advanced or MBC who have progressed following one prior chemotherapeutic regimen (FOPC). An economic model was developed to evaluate the cost-effectiveness of eribulin in HER2NEG MBC FOPC population in Spain. The data on progression free survival and overall survival was derived from randomized clinical trial of eribulin against capecitabine (study 301).  A five year partitioned survival model was developed to estimate the ICER of the patients in this sub-group. Health state utility data was obtained by mapping quality of life collected in study 301 to EQ-5D using validated algorithm. Frequencies of adverse events and utilization of direct medical resources were also obtained from study 301. Local Spain tariffs were applied for all costs i.e. drug, administration, adverse event treatment, and direct medical costs including hospitalization, physician visits, end of life and palliative care. RESULTS: Incremental life years (LYs) and Quality Adjusted Life Years (QALYs) gained by these patients were 0.26 and 0.23 respectively. At a cost of eribulin of €320 per vial, the ICERs per LY and QALY saved were €32,865 and €36,951 respectively. Sensitivity analysis results were also consistent with the basecase findings. CONCLUSIONS: According to reviewed HTA decisions in the past, eribulin was found to be cost-effective in 2L HER2NEG populations. Given the limited number of effective therapeutic options available to these patients, cost effective eribulin represents a valid option for optimizing the treatment pathways.