OBJECTIVE To investigate the microstructure of trabecular bone in adolescent idiopathic scoliosis (AIS) and age-matched congenital scoliosis (CS), and to evaluate the bone mineral status of CS patients compared with normal controls and AIS patients. METHODS This study included 15 AIS and 16 CS female patients and 35 healthy female adolescents. Corrective surgery was indicated for the AIS and CS patients, from whom iliac crest biopsies were collected during autograft harvesting, and scanned by micro-computer tomography. Bone mineral status was assessed at the lumbar and hip areas in every patient by dual energy X-ray absorptiometry (DEXA). RESULTS Significantly lower lumbar and femoral neck bone mineral density (BMD) was found in AIS patient compared with normal controls. All BMD and bone mineral content (BMC) parameters were significantly lower in CS patients compared with age-matched normal controls. Under DEXA assessment significant associations between bone volume/tissue volume (BV/TV) and BMD values were observed. In the 3D model, BV/TV was significantly higher in AIS (19.9% ± 3.4%) than in CS (13.3% ± 3.0%, P < 0.05). Significant differences between AIS and CS were also found in trabecular thickness (Tb.Th) and bone surface/bone volume (BS/BV) (155.5 ± 54.9 µm vs. 108.1 ± 17.4 µm and 16.4% ± 3.3% vs. 22.0% ± 3.4% respectively, P < 0.05 in both). CONCLUSIONS Lower bone mineral status and weak trabecular bone structure observed in AIS and CS justify further investigation of the bone mineral status in scoliosis of various etiologies.