We aimed to explore the long-term outcomes of back and neck pain and functionality in adult females with adolescent idiopathic scoliosis (AIS), who had been treated with a Milwaukee brace, in a follow-up study a minimum of 23 years after the completion of the treatment, using radiological, clinical and socio-demographical data. Thirty AIS patients (scoliosis group-SG), were included in the study based on an extensive search of Pediatric Orthopedics and Traumatology Clinic charts. All treatments were successfully completed between 1974 and 1990. In all cases, scoliosis had not been detected before the age of 10 and was not combined with any major spinal deformities at the time when the brace treatment was implemented. In those patients, the Risser sign 4 and minimum two years post-menarche was defined as a maturity, after that time the brace treatment was completed. Patients were excluded from the study if they, at the time of the follow-up examinations, suffered from any other disease leading to trunk deformity. Forty patients met the criteria for inclusion, but due to change some personal details, not all of them were contacted. Finally, 30 women returned for a follow-up evaluation. Patients' follow-up period was mean 27.77 yrs. ± SD 3.30 (range 23-35). Curvature change from the end of the treatment until the present day was mean 9.1 degrees ± SD 7.64 (range 0-27). A control group of 42 healthy females (healthy controls group-HG) matching the age profile of the patient group was randomly selected for comparative purposes.Both SG and HG completed the Polish versions of the Revised Oswestry Lower Back Pain Disability Index (RODI), the Rolland-Morris Questionnaire (RMQ), the Quebec Back Pain Disability Scale (QDS), the Neck Disability Index (NDI) and the Copenhagen Neck Functional Disability Scale (CNFDS). Descriptive statistics were calculated for demographics and baseline questionnaire scores. To determine if the investigated sample sizes are equivalent, the chi-square test was used. The chi-square test was used to compare qualitative features between persons with scoliosis and healthy controls. In addition, a Mann-Whitney test was utilized to compare differences between both groups in regard to quantitative characteristics. To establish relations between quantitative data such as e.g. age, duration of brace application, apical translation, Cobb angle, and questionnaire results, we used Spearman's rank correlation (marked as rS). To determine dependency between quantitative and qualitative characteristics, e.g. between questionnaire numerical data and marital status, place of residence or curve type, ANOVA Kruskal-Wallis test was used. A p<0.05 indicates statistical significance. Statistical calculations were performed by Statistica software. In regards to RODI, RMQ, QDS, NDI and CNFDS (both for total scores and particular sub-sections), statistically significant differences (p <0.001) between both samples were found, indicating higher levels of pain and neck and lower back pain-related disability among persons with scoliosis. Associations exist between RODI and RMQ (rS = 0.76) QDS (rS = 0.70), NDI (rS = 0.69) and CNFDS (rS = 0.60). RMQ was associated with QDS (rS = 0.71) and NDI (rS = 0.69), whereas QDS correlated with NDI (rS = 0.80) and CNFDS (rS = 0.60). NDI was also associated with CNFDS (rS = 0.81). Persons with scoliosis treated in adolescence with a Milwaukee brace display significant restrictions in everyday activities, due to lower back pain (LBP) and neck-related disabilities, compared to healthy controls. In addition, back pain is associated with curve progression in long-term follow-up after conservative treatment. Moreover, LBP-related disability coexists with restrictions experienced due to neck pain.