Objective: With the advent of the anaplastic lymphoma kinase (ALK) inhibitor, treatment of ALK-positive advanced non-small-cell lung cancer (NSCLC) patients has become more effective while drug costs are still a major concern. This study aimed to estimate the budget impact of crizotinib versus other standard therapies in Thai advanced NSCLC patients with ALK rearrangement.Methods: The budget impact model was developed to estimate the net budget impact of crizotinib compared with no crizotinib considering the payer's perspective over a three-year period. Costs included drugs, ALK testing by FISH, adverse event treatment, administration and monitoring, and best supportive care. Data on costs and population were from a database in Thailand. Costs were presented for the year 2015. A univariate sensitivity analysis was performed to investigate the robustness of our findings.Results: The total net budget impact of crizotinib in three years was 125,576,699 THB (3,480,507 USD), 91,156,049 THB (2,526,498 USD), and 42,724,760 THB (1,184,167 USD) respectively. When considering only patients receiving crizotinib, the expenditure increased by 41,199.70 THB (1141.90 USD), 20,755.02 THB (575.25 USD), and 8834.73 THB (244.87 USD) per patient per month. The main driven costs were from the cost of ALK testing and drugs.Conclusion: Despite its treatment value in ALK-positive patients, crizotinib can only be affordable for Thai patients within upper middle or high economic status. Availability for all patients under current payment models is limited.