Verify the influences of physical activity level, nutritional status and screen habits on the prevalence of back pain in Brazilian students. The sample consisted of 577 schoolchildren (female = 274; male = 303) aged between 10 and 16 years old, regularly enrolled in the 6 grade of elementary school living in the metropolitan area of the Alto Tietê of the state of São Paulo, Brazil. The prevalence, intensity and frequency of pain was verified with the Back Pain Assessment Instrument. The usual practice of physical activity was verified with the Physical Activity Questionnaire for Older Children/Adolescent. Nutritional status was analyzed using Body Mass Index. Screen habits were obtained through a previously structured questionnaire. The Chi-square test indicated that pain complaint and its prevalence in the cervical region are significantly higher in females (p < 0.05). The multiple logistic regression test revealed that watching television influences the prevalence of cervical pain and that the use of more than one screen increases the occurrence of low back pain in male students (p < 0.05). Female students were the most affected by back pain complain, especially in the cervical region. However, factors associated with the prevalence of back pain were found only in males.