OBJECTIVE: To evaluate the effectiveness of AML-XH-99-M3 protocol for treatment of acute promyelocytic leukemia (APL) in children.METHODS: Thirty-three children with APL received AML-XH-99-M3 protocol treatment. The event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) were evaluated by the Kaplan-Meier medthod with SPSS13.0 software.RESULTS: Thirty patients (90.9%) achieved a complete remission (CR) after one course of treatment. The total CR rate was 100%. Six patients (18.2%) relapsed in an average of 29.17 months (16-38 months). Two patients (6.1%) died. The 7-year EFS and DFS in the 30 patients were 73.4±9.4%. The overall survival rate was 91.2±6.0%. The difference of EFS was observed in patients receiving intermittent all-trans-retinoic acid (ATRA) administration or not in the maintenance therapy (88.9±10.5% vs 62.5±13.6%) (P<0.05).CONCLUSIONS: The AML-XH-99-M3 protocol for the treatment of APL produced a higher CR rate and higher EFS, DFS and OS rates in children. Intermittent administration of ATRA in the maintenance therapy can improve EFS rate.