OBJECTIVES: A Budget Impact Model (BIM) was developed to assess the impact on Italian National Health Service (NHS) expenditure caused by the use of tocilizumab (TOC) , monoclonal antibody approved by EMA in early 2009, as a first-line biologic treatment vs. traditional anti-TNFα therapies in the treatment of moderate to severe rheumatoid arthritis (RA) patients. METHODS: A Markov model was used to simulate the progression of a cohort of RA patients through three lines of biologic treatments with anti-TNFα and TOC, palliative therapy and death. The horizon was five years. The target population was defined by the number of incident RA patients eligible to first-line biologic treatment based on Italian epidemiological and market data. First-line TOC followed by a second- and a third-line anti-TNFα treatment was compared a more traditional strategy based on anti-TNFα cycling. Direct medical costs were considered: drug acquisition, administration and monitoring tests, according to current prices and tariffs. To estimate the relative effectiveness of use of economic resources, the average number of patients that can be treated with an hypothetical annual budget of €1,000,000 was assessed. RESULTS: Italian RA patients eligible to a first-line biologic therapy were estimated in 750 per year. First-line TOC strategy induced a decrease of costs of €805,000 (-8.6% with respect to anti-TNFα cycling), and €1,348,000 (-3.1%) at  year1 and year5 respectively. The average annual number of patients that can be treated with €1,000,000 was 75.7 at year1 and 78.5 at year5 under the anti-TNFα cycling strategy, while it was 82.9 at year1 and 81.8 at year5 with first-line TOC, with a 9.5% to 4.3% increase. CONCLUSIONS: The introduction of TOC among the biologic therapies available for Italian RA patients represents a valuable option as it is expected to induce a reduction in costs and a more efficient use of health care resources.