OBJECTIVES: In Costa Rica, Caja Costarricense de Seguro Social (CCSS) doesn’t include fulvestrant in its basic drug list, however it’s authorized for individual cases of women with metastatic breast cancer after receiving two lines of hormone therapy. This study aims to assess the results obtained in patients that received treatment with fulvestrant in CCSS between 2012 and 2015, and the cost-effectiveness (efficiency) of intervention. METHODS: This is an observational, retrospective, descriptive study, that includes the patients that were authorized to receive treatment with fulvestrant, according to the data base of the Central Pharmacotherapy Committee, between January 2012 and December 2015. Clinical records were accessed to retrieve information on diagnosis, hormone receptors, ECOG, treatment duration, progression-free and overall survival, and cost of treatment. RESULTS: