OBJECTIVES: To estimate the cost-effectiveness of dasatinib and nilotinib compared with high-dose imatinib for people with chronic phase chronic myeloid leukemia, which are resistant to normal-dose imatinib and compared with interferon-α for people intolerant to imatinib, from the perspective of the UK National Health Service. METHODS: An an area under the curve partitioned survival model was developed to estimate the cost-effectiveness of dasatinib and nilotinib. Clinical effectiveness evidence was taken mostly from single-arm trials. RESULTS: Both progression-free survival and overall survival are highly uncertain. In the base case, patients take nilotinib for much less time than dasatinib. Nilotinib is expected to dominate high-dose imatinib, yielding slightly more (0.32) quality-adjusted life years (QALYs) at slightly less cost (£11,100 [pound sterling]) per person. Dasatinib is predicted to provide slightly more (0.53) QALYs at substantially greater cost (£48,900), yielding a very high incremental cost-effectiveness ratio of £91,500 QALY against high-dose imatinib. Cost-effectiveness, however, changes radically under the plausible assumption that the drugs are taken for the same time. For people intolerant to imatinib, nilotinib is expected to yield an incremental cost-effectiveness ratio of £104,700/QALY, and dasatinib £82,600/QALY compared with interferon-α. Further, both drugs represent poor value for money for a range of plausible structural assumptions. CONCLUSIONS: The model should be viewed as an exploratory analysis of the cost-effectiveness of dasatinib and nilotinib because it relies on many assumptions. Whilst clinical data remains immature, the cost-effectiveness of dasatinib and nilotinib for imatinib-resistant people is highly uncertain. Both nilotinib and dasatinib are highly unlikely to be cost-effective versus interferon-α for people intolerant to imatinib.