Purpose: ALK-targeted therapy with crizotinib offers significant improvement in clinical outcomes for the treatment of EML4-ALK fusion-positive non-small-cell lung cancer (NSCLC). We estimated the cost effectiveness of EML4-ALK fusion testing in combination with targeted first-line crizotinib treatment in Ontario., Patients and Methods: A cost-effectiveness analysis was conducted using a Markov model from the Canadian Public health (Ontario) perspective and a lifetime horizon in patients with stage IV NSCLC with nonsquamous histology. Transition probabilities and mortality rates were calculated from the Ontario Cancer Registry and Cancer Care Ontario New Drug Funding Program (CCO NDFP). Costs were obtained from the Ontario Case Costing Initiative, CCO NDFP, University Health Network, and literature., Results: Molecular testing with first-line targeted crizotinib treatment in the population with advanced nonsquamous NSCLC resulted in a gain of 0.011 quality-adjusted life-years (QALYs) compared with standard care. The incremental cost was Canadian $2,725 per patient, and the incremental cost-effectiveness ratio (ICER) was $255,970 per QALY gained. Among patients with known EML4-ALK-positive advanced NSCLC, first-line crizotinib therapy provided 0.379 additional QALYs, cost an additional $95,043 compared with standard care, and produced an ICER of $250,632 per QALY gained. The major driver of cost effectiveness was drug price., Conclusion: EML4-ALK fusion testing in stage IV nonsquamous NSCLC with crizotinib treatment for ALK-positive patients is not cost effective in the setting of high drug costs and a low biomarker frequency in the population.