OBJECTIVES: A relative value analysis (RVA) of first-line treatments for chronic myeloide leukemia, dasatinib and imatinib, was performed from the Spanish National Health System perspective. METHODS: A decision model was built according to the European Leukemia Net recommendations. Response and tolerance were assessed based on trial outcomes. The model was run for 1,000 patients initiated on dasatinib (100mg, QD) or imatinib (400mg QD). Dose adjustments or treatment switches for limited response or intolerance were allowed. Ten different cost levers were identified for four sources of value (response, adverse event, adherence and monitoring). Total cost (€, 2012) was estimated over 5-years, with an annual 3% discount rate, by sum of the cost levers and drugs cost (ex-factory price with 7.5% mandatory rebate). Data sources included literature, health costs database and expert opinion. Sensitivity analyses (SA) were performed.  RESULTS: The final incremental total cost of dasatinib compared to imatinib, resulting from the RVA was €3,355 per patient per year. Difference in drug cost of dasatinib is estimated to be €11,363/patient/year compared to imatinib. Monitoring and treatment of adverse events increased costs by €36/patient/year with dasatinib. Dasatinib, however, is associated with savings in other costs: cases of low dose regimens saved €65/patient/year. Switching for limited response or intolerance decreased costs by up to €6,819 and €563/patient/year respectively, with dasatinib. Costs of non-adherence and other additional management were reduced €466 and €132/patient/year with dasatinib vs imatinib. The SA showed further reductions in the incremental cost of dasatinib when longer term cost savings were included or the share of imatinib patients after intolerance or limited response was increased. CONCLUSIONS: The incremental drug cost of dasatinib vs imatinib €11,363 per patient/year (31%) is reduced to €3,355/patient/year (9%) if the cost consequences of the events over 5 years are considered.