OBJECTIVES: Nearly 90% of all dialysis performed in Brazil is done by hemodialysis (HD). A recent estimates shows that the annual direct cost of providing HD by the Brazilian government is $7,980 per patient. It is also been estimated that end-stage renal disease (ESRD) is growing annually at 10.1%, yet approximately 25% of patients are not treated. The objective of the present study was to estimate the impact of treating a growing and underserved ESRD population on government expenditures. METHODS: An Excel-based budget impact model (BIM) was used to estimate the cumulative 5-year impact of an increase in the treatment of ESRD patients using HD. The year 2006 was the baseline and the model projected costs out to 2011. At baseline, there were 62,300 HD patients. The model assumed an annual ESRD growth rate of 10.1%. The direct costs of HD were held constant at $7,980 over the five-year projection. Costs are from the government point of view. It was assumed that 25% of ESRD patients are currently untreated. RESULTS: At baseline, the total direct cost of HD is $358 million. If there were no growth in ESRD, the 5-year cumulative treatment costs would be $2.15 billion. However with a 10.1% ESRD growth, the cumulative 5-year costs would be $2.77 billion, a net increase of $621 million. In addition, if HD treatment is provided to all untreated patients with ESRD (20,767 additional patients at baseline), the cumulative 5-year budget increases to $3.7 billion. CONCLUSION: Treatment of ESRD patients with HD is substantial. If the government of Brazil targets to treat all patients with HD, the costs of dialysis would skyrocket. To keep these patients alive with a good quality of life, the government should look more closely at other modes of dialysis that are both clinically effective and cost saving.