Background/aim: This study was performed to show the efficacy of in situ local autograft with a comparison of in situ local autograft, local autograft with allograft, and local autograft with posterior iliac crest autograft.Materials and methods: In this prospective randomized study, a total of 65 adolescent idiopathic scoliosis (AIS) patients were separated into 3 groups: Group 1 using local autograft and allograft, Group 2 using local autograft only, and Group 3 using local autograft and posterior iliac crest autograft. Posterior segmental instrumentation was also applied to all patients. The mean follow-up period was 28.5 months (range, 15-40 months). Pseudarthrosis was investigated with the multiplanar and three-dimensional images obtained using multislice computed tomography, thoracolumbar bone single-photon emission computed tomography, and three-phase regional and whole body bone scintigraphy. Results: Pseudarthrosis was not observed in any patient. Fusion was obtained in all patients at the end of the follow-up periods.Conclusion: Similar results were obtained in respect of fusion in all 3 groups. Without the use of additional grafts, sufficient fusion can be achieved with the use of local autograft alone for posterior spinal fusion in patients with AIS.