The aim of the study was to identify the effectiveness of posterior pedicle screw instrumentation without osteotomy in the management of adolescent idiopathic scoliosis (AIS).The AIS patients underwent standing anteroposterior and lateral radiography before and after surgery. Age, sex, Lenke type, preoperative and postoperative Cobb angle, and all the related complications were recorded at final follow-up.We investigated data from 137 AIS patients who underwent posterior pedicle screw instrumentation without osteotomy from January 2012 to January 2016 with >2 years follow-up. Mean age was 14.3 ± 1.5 years at operation. The preoperative and latest postoperative coronal Cobb angle was 60 ± 12° and 9 ± 5°, respectively. Additionally, complications were noted in 6 patients. However, the prognosis of all the AIS patients was good, and the satisfaction of the Scoliosis Research Society Outcomes Instrument (SRS-22) questionnaire was 4.4 ± 0.5 at final follow-up.In the management of mild and moderate AIS, satisfactory clinical results can be obtained using posterior pedicle screw instrumentation without osteotomy.