Nilotinib has significant efficacy in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP) and in patients with CML-CP or CML in accelerated phase (CML-AP) after imatinib failure. We investigated the occurrence of cross-intolerance to nilotinib in imatinib-intolerant patients with CML. Only 1/75 (1%) patients with nonhematologic imatinib intolerance experienced a similar grade 3/4 adverse event (AE), and 3/75 (4%) experienced a similar persistent grade 2 nonhematologic AE on nilotinib. Only 7/40 (18%) patients with hematologic imatinib intolerance discontinued nilotinib, all because of grade 3/4 thrombocytopenia. Ninety percent of imatinib-intolerant patients with CML-CP who did not have complete hematologic response (CHR) at baseline (n = 52) achieved CHR on nilotinib. Nilotinib induced a major cytogenetic response in 66% and 41% of patients with imatinib-intolerant CML-CP and CML-AP (complete cytogenetic response in 51% and 30%), respectively. Minimal cross-intolerance was confirmed in patients with imatinib-intolerant CML. The favorable tolerability of nilotinib in patients with imatinib intolerance leads to alleviation of AE-related symptoms and significant and durable responses. In addition to its established clinical benefit in patients with newly diagnosed CML and those resistant to imatinib, nilotinib is effective and well-tolerated for long-term use in patients with imatinib intolerance. This study is registered at http://www.clinicaltrials.gov as NCT00471497.