The adequate dose of imatinib has not been defined for the Japanese population. Indeed, about half of patients experience mild to moderate adverse events due to this drug, some of which result in intolerance. We reviewed a patients' cohort treated with imatinib in our hospital in 2007 for chronic myelogeneous leukemia (CML). The cohort included 14 patients (5 men and 9 women) whose median age was 53 (range 16-81). The disease status at onset was chronic phase in 13 patients and accelerated phase in 1. During the 2-year observation period, 2 patients (14%) failed to respond and 6 (42%) became intolerant to imatinib. After the appearance of the intolerance, 5 of the 6 patients were treated with a reduced dose of imatinib (300 mg/day in 4, 200 mg/day in 1). In 4 of these 6 intolerant cases, CR was maintained 2 years after the start of imatinib therapy. Nevertheless, 42% of patients were intolerant to imatinib therapy through 2 years, and progression-free survival was 86%. In conclusion, an adjusted dose exerting minimal toxicity and showing a favorable outcome should be researched in Japanese patients including the elderly.