OBJECTIVES: The oral formulation of fludarabine phosphate is equivalent to the IV formulation in terms of clinical efficacy, in previously untreated B-CLL. The objective of this evaluation is to perform a cost minimization analysis. METHODS: To conduct this evaluation the following parameters were considered: acquisition value of the IV and oral fludarabine by the public health system (PHS); resources consumption for IV fludarabine application; toxicity profile of the two presentations based on literature data; adverse events management and their resource consumption according to the Inca; PHS reimbursement for the patients hospitalized with LCC; an index patient with 1.69 m2 body surface area and 60 years old; oral and IV fludarabine dose of 40mg/m2 and 25mg/m2 respectively. The treatment cost of a given adverse event was considered to be the same irrespectively to the fludarabine presentation. RESULTS: Although oral fludarabine presented a lower cost per mg in comparison to the IV formulation (R$9.85 vs. R$10.20) the total drug cost for the whole treatment is greater for the oral formulation than for IV (R$20,676.60 vs. R$15,300.00). However considering that the administration cost per cycle of the IV formulation is R$956,80 the overall cost of IV fludarabine becomes higher than the oral formulation (R$22,150.78 vs. R$23,160.31). The cost of the treatment of each considered adverse event for oral and IV fludarabine were respectively: infection (339.72 vs. 519.99); neutropenia (962.79 vs. 1187.75), anemia (106.02 vs. 222.74), diarrhea (11.97 vs. 0.00), nausea (2.25 vs. 7.11) and thrombocytopenia (52.47 vs. 182.05). Overall IV fludarabine costs 4.56% more than its oral formulation. CONCLUSIONS: This preliminary analysis shows that oral fludarabine has lower total cost per patient with similar efficacy to IV fludarabine with lower adverse events and administration costs. A cost effectiveness analysis should confirm these promising data