Chronic myeloid leukemia (CML) is a rare disease in children, accounting for 2-3% of leukemias in this age group. Few studies have reported on efficacy of imatinib in childhood CML. The purpose of this retrospective study was to determine the efficacy of imatinib in children. A total of 43 patients from age 7 years to 20 years with newly diagnosed CML received imatinib daily at 260 mg/m(2). Response rates, survival and toxicity were evaluated. The median follow-up was 43 months. All patients achieved a complete hematological response. Twenty-five (58.1%) patients achieved a complete cytogenetic response and 18 (41.9%) achieved a major molecular response at any time during their follow-up period. Both overall survival and progression-free survival at 43 months' median follow-up were 100%. Event-free survival was 92.8%. Imatinib was well tolerated. We conclude that imatinib is effective in children and adolescents with CML.