OBJECTIVES: To compare costs of two delivery systems (pen vs. vials/syringes) of recombinant human growth hormone (rGH) in Brazilian GH deficient patients. METHODS: A budgetary impact model was developed to calculate total costs based on product waste (difference between prescribed dose and actual delivered dose, based on dosing increments for pens [Pfizer Gocquick 16UI and 36UI – P16 and P36, respectively] and a fixed-percent waste described in the literature for vials [Hormotrop 4UI and 12UI – V4 and V12, respectively]) and drug cost. Annual acquisition costs were calculated based upon total milligrams delivered, for pediatric and adult patients. Dose was 0,03mg/kg/day for children and 0,15mg/day for adults. It was considered both public and private payer perspectives. RESULTS: For children, calculated waste was 2.56% and 7.69% for P16 and P36, respectively; for adults, it was 0% for both versions. Waste for vials was fixed in 23% for all scenarios. From the public payer perspective, total cost per treatment-year for children was BRL26,256.96, BRL25,396.38, BRL33,702.73 and BRL32,683.92 for P16, P36, V4 and V12, respectively and waste cost was BRL2,019.77, BRL1,953.57, BRL7,751,63 and BRL7,517.30; for adults, total cost per treatment-year was BRL3,750.99, BRL3,628.05, BRL5,185,04 and BRL5,028.30 for P16, P36, V4 and V12, respectively and waste cost was BRL0.00, BRL0.00, BRL1,192.56 and BRL1,156,51. From the private payer perspective, total cost per treatment-year was, respectively, BRL32,027.03, BRL32,526.11, BRL43,164.19 and BRL41,858.67 for P16, P36, V4 and V12, and waste cost was BRL2,586.80, BRL2,502.01, BRL9,927.76 and BRL9,627.49 in children; for adults, total cost per treatment-year was BRL4,804.05, BRL4,646.59, BRL6,640.64 and BRL6,439.79 for P16, P36, V4 and V12, respectively and waste cost was BRL0.00, BRL0.00, BRL1,527.35 and BRL1,481.15. CONCLUSIONS: For pediatric and adult patients, rGH administration through pens was less costly, and had less waste than vials/syringes, from both public and private perspectives. P36 use was the best option in this analysis.