Study design: Cross-sectional study. Objective: To evaluate the association between back pain and health-related quality of life (HRQoL) among adolescents. Summary of background data: The prevalence of back pain has been increasing not only in the adult population but also among children and adolescents. The better knowledge about the association between back pain and health-related quality of life could facilitate the implementation of new intervention strategies on prevention and treatment of back pain. Methods: A sample of 350 students from the fifth to ninth grades of one public school in Niterói, Rio de Janeiro, Brazil. Anthropometric measures and information regarding sociodemographic, lifestyle, frequency and intensity of neck (NP), thoracic (TP), and low back pain in the previous month were collected using a personal digital assistant. HRQoL was assessed by KIDSCREEN-27. Multiple linear regression analyses were performed to investigate the association between back pain and HRQoL by sex. Results: The mean age of participants was 12.7 (1.6) years. Frequency of NP, TP, and low back pain was 34.3, 27.1, and 13.1%, respectively. The mean intensity of pain was 2.3 (0.2) for neck, 2.0 (0.2) for thoracic, and 1.3 (0.1) for low back pain. The presence of two/three painful sites was reported by 21.7% of the adolescents. The frequency and severity of neck pain were inversely associated with global HRQoL in both the sexes. There is a strong inverse association between the number of painful sites and global HRQoL and domains. Conclusion: The presence and intensity of cervical pain and the number of painful regions were associated with lower HRQoL in adolescents, which is worrying due to the important relationship between back pain in the adolescence and in the adulthood.2020-07-18