Background & objectives: Most tobacco users who initiate its use during adolescence are likely to continue the use into adulthood and contribute to the 90 per cent of premature deaths among tobacco users. In this context the prevalence, patterns and correlates of tobacco use were studied among adolescent school students in Kerala, India. Methods: Total 7560 students from classes 8, 10 and 12, within the age group of 12-19 yr, across 73 schools in Ernakulam district, Kerala, India, selected by cluster random sampling, completed a self-administered questionnaire incorporating standardized instruments. Results: Of the 7350 valid questionnaires, the overall lifetime prevalence of tobacco use was 6.9 per cent (12.5% males and 1.2% females). The prevalence of tobacco use increased from 3.1 per cent at 12-13 yr to 15.1 per cent at 18-19 yr. The mean age of onset of tobacco use was 14.0±2.2 yr. The prevalence was higher among students from urban backgrounds, lower socio-economic status and those with part-time jobs. Tobacco users had significantly higher rates of use of alcohol (67.8 vs. 11%) and illicit drugs (33 vs. 6.1%). They had poorer academic performance (24.7 vs. 9.1%), more severe psychological distress (10.8 vs. 4.5%), suicidal attempts (10.2 vs. 3.5%), higher scores of ratings of attention deficit hyperactivity disorder (8.3 vs. 2.5%) and history of sexual abuse (12.5 vs. 3.8%). Interpretation & conclusions: The prevalence of tobacco use in adolescents reported in this study was relatively lower than those reported from other Indian States. However, it correlates with multiple negative outcomes suggesting a need to promote specific interventions to prevent adolescent tobacco use.