Background. Although survival rate approaches 90% for most children with acute lymphoblastic leukemia (ALL), adolescents and young adults (AYA) historically have a poorer prognosis. Previous reports suggested that the survival of AYA patients had improved when treated with pediatric-based treatment. The purpose of this study was to analyze the treatment outcome of AYA patients who were treated with the pediatric ALL protocol. Methods. We retrospectively analyzed the outcome of AYA ALL patients who were treated at our pediatric hemato-oncology department. Between January 2004 and December 2016, 21 AYA patients aged 15 to 21 years were treated with pediatric protocols. Results. Median age at diagnosis was 16 years and median follow-up was 40.1 months. T cell ALL was present in five (24%) patients, and 76% patients had B cell ALL. The median white blood cell count at presentation was 33,295/μL (range: 2,140 – 343,380/μL). Three patients had BCR-ABL1 fusion gene, two had MLL rearrangement, however, no patient had evidence of the TEL-AML1 fusion gene. We identified induction failure in three (14%) patients, two of these were patients with T-cell ALL. Relapse occurred in three (14%) patients, all of these were within 6 months off-therapy. Seven patients received allogenic hematopoietic stem cell transplantation and five patients achieved complete remission. Seven patients died, overall survival (OS) and event-free survival (EFS) were 67% and 62%, respectively. Conclusions. AYA ALL still have shorter OS and EFS than younger children. Considering the historical EFS of only 30% to 45%, however, AYA patients with ALL benefited from pediatric-based protocol.