BACKGROUND: Assessing the quality of life (QOL) of children with early onset scoliosis (EOS) has been discussed recently. Therefore, the study aimed to apply and correlate the 24-item Early Onset Scoliosis Questionnaire (EOSQ-24) with the 50-item Childhood Health Questionnaire (CHQ-PF50) to find predictive factors impacting QOL. METHODS: Cross-sectional study involving a population of caregivers of patients with EOS. The sample consisted of 72 patients. Two research assistants applied the Portuguese version of the EOSQ-24 and CHQ-PF50 in 3 treatment centers. The EOSQ-24 assesses the subjective response of children with EOS from the parent's point of view. The CHQ is a self-administered questionnaire or parental proxy assessment of the psychological and social status of children aged 5 to 18 years. RESULTS: Of 72 patients, 41 (56.9%) were females, mean age of 11.9 ± 4.2 years. The most common scoliosis was of neuromuscular origin (32%). The CHQ-PF50 showed that family-related items had significant scores. The most affected subcategory was physical function (45.5), and the least affected was mental health (90.8). Thus, the CHQ-PF50 PhS summary index was 27, and the CHQ-PF50 PsS was 71.7. Moreover, the critical categories for the EOSQ-24 questionnaire were daily life and physical function (45.1 and 47.8, respectively), and the least affected categories were transfer and pulmonary function (70.8 and 68.9, respectively). Four subcategories showed a strong correlation between both questionnaires: general health (r = 0.749, P < 0.001), physical function (r = 0.645, P < 0.001), bodily pain (r = 0.714, P < 0.001), and mental health (r = 0.424, P < 0.001). Using CHQ-PF50 as a dependent variable in multiple regression analysis (P = 0.028), the only variable affecting the scores was syndromic scoliosis (P = 0.019; 95% CI -27.4 to -2.5). CONCLUSION: A strong correlation between both questionnaires was seen for general health, physical function, bodily pain, and mental health. Syndromic scoliosis was a predictor of worse QOL according to the CHQ-PF50.