Since hematology is a highly specialized field, an individual physician may not have much direct treatment experience with a given disease. Therefore, the Japanese Society of Hematology (JSH) has discussed establishing a registry of hematologic disorders, in order to contribute to improving the quality of treatments and clinical outcomes in this field. As a first step, the Timely and Appropriate Registration System for GLIVEC Therapy (TARGET), a registration system for chronic myeloid leukemia (CML) patients treated with imatinib, was established in October 2003. We present the preliminary results of the first 4 years' experience with this system. CML patients treated with imatinib in Japan were registered through the website and the patient's clinical course, including parameters and events like imatinib dose, blood counts, adverse events, and efficacy were recorded in months 1, 3, 6, 9, and 12 and then every 6 months thereafter. By September 2007, 862 patients from 176 hospitals were registered. Follow-up period was 0-54 months, and 127 patients were followed-up for more than 36 months. Based on these cumulative data, present imatinib treatment trends were analyzed and safety and efficacy were compared with international trial data.