OBJECTIVES: In the treatment of locally advanced and metastasized stage of non-small cell lung cancer (NSCLC), the first line of medication is comprised of a combination of cisplatin and gemcitabine. The second line of treatment is the combination of carboplatin and paclitaxel, and the third line is pure erlotinib. A new treatment scenario has been designed which uses the new medication, gefitinib, that acts as an inhibitor of the epidermal growth factor receptor tyrosine-kinase (EGFR-TK), which blocks growth signals and prevents the subsistence of cancer cells. The aim of this study is to assess the potential financial impact of the introduction of gefitinibinto the treatment of metastasized NSCLC. METHODS: The study conducted a budget impact analysis, which was meant to determine the difference in cost between the treatment with gefitiniband the established treatment, so as to provide justification for the introduction of the new drug. RESULTS: Direct costs per patient with a proven positive EGFR mutation (5%) treated with the new drug gefitinib, amount to 171.194,00 HRK, while costs for other patients treated with the established medication, amount to 168.793,90 HRK, which shows that the total cost for the new treatment scenario is somewhat higher. The total direct cost for an established treatment scenario is 139.236.532, 10 HRK, while the new scenario amounts to 142.270.005,50 HRK. Scientific observations point to the fact that gefitinibhas a higher drug tolerance and better effectiveness among patients diagnosed with an EGFR mutation. CONCLUSIONS: A budget impact analysis shows that 28 patients will be treated with gefitinib in the year 2012, and 96 in the year 2014, which will increase the budget impact by 3%. However, a lowering in administration, patient monitoring and side-effects treatment costs are expected, making the total budget impact of the gefitinib introduction into treatments practically neutral (0,07%).