To achieve successful therapeutic outcomes in chronic myeloid leukemia (CML), continuous and adequate imatinib (Gleevec(®), Glivec(®), Novartis Pharmaceuticals, Basel, Switzerland) dosing is essential. Here, we report a patient counseling program ("Care club", "Happy club" in Korea) performed to improve patient compliance with imatinib. From January 2006 to December 2008, patients diagnosed with chronic phase CML and taking imatinb were eligible for this retrospective study. A total of 114 patients from 4 centers in Korea were recruited at a 50:50 ratio for Happy club group versus non-Happy club group at each center. During 36-month follow-up, persistency (the number of days of imatinib prescribed versus 1 year) was higher in the Happy club group (98.2 ± 0.03%) than in the non-Happy club group (79.3 ± 0.16%, P = 0.001), whereas dose compliance (miligrams of imatinib that were actually taken versus miligrams that should have been taken) was not different between two groups; 96.5 ± 0.6% and 96.6 ± 0.7% in the Happy club and non-Happy club (P = 0.958). Overall compliance (the product of persistency and dose compliance) improved in the Happy club group (93.0 ± 2.3%) compared with the non-Happy club group (76.2 ± 7.4%, P = 0.001). The patient counseling program was efficient especially in patients who needed high-dose imatinib (>400 mg/day), and overall compliance was 87.8 ± 6.0% in the Happy club group versus 65.5 ± 16.1% in the non-Happy club group (P = 0.017). In conclusion, the patient counseling program was effective in persisting imatinib medication, resulting in the improvement of overall compliance.