Chronic myeloid leukemia (CML) with T315I mutation has been reported to have poor prognosis. We analyzed 27 patients with T315I, including 20 who developed T315I after imatinib failure (representing 11% of 186 patients with imatinib failure), and 7 of 23 who developed new mutations after second tyrosine kinase inhibitor (TKI). Median follow-up from mutation detection was 18 months. At the time of T315I detection, 10 were in chronic phase (CP), 9 in accelerated phase, and 8 in blast phase. Except for the lack of response to second TKIs (P = .002), there was no difference in patient characteristics and outcome between patients with T315I and those with other or no mutations. Patients in CP had a 2-year survival rate of 87%. Although the T315I mutation is resistant to currently available TKIs, survival of patients with T315I remains mostly dependent on the stage of the disease, with many CP patients having an indolent course.