ESP are standard treatment options for CIA. In this setting, both Epoetin(EPO)alfa and EPObeta are administered three times/week(TIW) or once/week(QW), while darbepoetin alfa(DA) is the only ESP approved to be administered as once every three weeks(Q3W). For ESP administered TIW or QW the SPCs states to double the dose if hemoglobine increases<1g/dL after 4weeks. Doubling the dose is not needed with starting dose DA500µgQ3W. These administration differences might result in different treatment costs for each agent. OBJECTIVE: Estimate BI (mean cost/patient) of administering the different ESP in the treatment of CIA in Spain. METHODS: The following variables were considered in the economic model:ESP ex-manufacturer price in Spain, administration pattern, weeks of treatment(12 weeks), weeks of evaluation before increments of dose(4 weeks), dose increases, and overall cost of one administration(€59.72). In addition, a two-way sensitivity analysis was performed to test the robustness of the results, considering the following variables:1)administration cost from a minimum of 0 to +25%, and 2)the lowest and highest percentage of patients needing to increase dose for EPOalfa and EPObeta from six studies found in the literature where this data was reported. RESULTS: In the base case scenario, assuming an incidence of doubling the dose with both EPOalfa and EPObeta of 29.60%, which was the mean value found in the literature(min 22.90%, max 42.80%), treatment with starting dose DA500mgQ3W resulted in a BI that were 35.64% and 27.64% lower than EPOalfa 10.000UI TIW and 40.000UI QW respectively and 35.59% and 17.11% lower than EPObeta 10.000UI TIW and 30.000UI QW respectively. The results of the base case did not change in any of the sensitivity scenarios. CONCLUSION: The model shows that treatment of CIA with starting dose DA500mgQ3W is the therapeutic strategy with lower mean cost per patient for all the analyzed scenarios in Spain.