Background: Severe early-onset scoliosis (EOS) is managed surgically but represents a challenge due to limited implant fixation points, large curve size, and fragile patients with comorbidities. Magnetically controlled growing rods (MCGRs) have the advantage of avoiding surgical intervention for routine lengthening, but their ability to address severe EOS has not been studied, to our knowledge.Methods: A retrospective review of a prospectively collected international database identified 44 children with severe ( ‡90°) EOS treated with MCGRs who met our study criteria. Etiology, age, and sex-matched patients treated with traditional growing rods (TGRs) were identified from the same database. Patients were evaluated at a 2-year follow-up. No patients with vertically expandable prosthetic titanium ribs (VEPTRs) were included. The health-related quality of life was evaluated with the 24-Item Early Onset Scoliosis Questionnaire (EOSQ-24).Results: The mean preoperative major coronal curve was 104°in the MCGR group and 104°in the TGR group. At the 2-year follow-up, the mean major coronal curves were 52°and 66°(p = 0.001), respectively. The mean T1-T12 heights were 155 mm and 152 mm preoperatively and 202 mm and 192 mm at the 2-year follow-up (p = 0.088). According to Kaplan-Meier analysis, the 2-year unplanned-revision-free survival was 91% in the MCGR group and 71% in the TGR group (p < 0.005). The 2-year score in the EOSQ-24 pulmonary function domain was better in the MCGR group. There were no other significant differences in the EOSQ-24 scores between the groups.Conclusions: MCGRs for severe EOS provided significantly better major curve correction with significantly fewer unplanned revisions than TGRs at a 2-year follow-up.