Traditionally, the effectiveness of brace treatment on adolescents with IS is based on curve magnitude and to some extent on vertebral rotation and rib hump. QoL has been introduced in the recent years in order to evaluate the effectiveness of brace treatment. The aim of the study is to determine the influence of brace on quality of life (QoL) of adolescents with idiopathic scoliosis (IS).Thirty-six patients with a mean age of 13,9 (range 12-17) years old, a mean Cobb angle 28,2 degrees (range 19-38 degrees and a mean angle of trunk inclination (ATI) 7,8 degrees (range 4 degrees -17 degrees) who were treated conservatively with a modified Boston brace for a minimum of 2 years, filled the form of Brace Questionnaire (BrQ). BrQ is a validated, disease specific instrument, its score ranges from 20 to 100 and higher BrQ scores mean better quality of life. Correlations were determined by the Pearson correlation coefficient, with p<0.05 considered significant. Mean overall score of BrQ was 73,8 (SD 15. 8). Lower scores were observed in physical functioning (55,4, SD 15,9) and vitality (55, SD 25,9). School activity (98, SD 4,4) was affected less. The Cobb angle correlated significantly only with school activity (p<0,02). The ATI correlated significantly with social functioning (thoracolumbar ATI, p<0.038; lumbar ATI, p<0.035). There were no significant correlations between either Cobb angle or ATI with BrQ overall scores. Cobb angle and ATI significantly influenced school activity and social functioning respectively, but not general health perception, physical functioning, emotional functioning, vitality, bodily pain and self-esteem and aesthetics.