OBJECTIVES: Valid screening tools are needed to identify Indian children and adolescents with mental health problems, both for clinical or research purposes. The present study validated the Strengths and Difficulties Questionnaire (SDQ) in Malayalam across different informants and sub-scales. METHODS: A sample of 150 children and adolescents seen in a psychiatric clinic for children in Kerala, India was compared to a community sample of 1984 children from six surrounding urban and rural districts. Children in clinic and community samples were screened with the parent-report SDQ; those over 11 y completed the self-report SDQ. The community sample was also screened with the teacher-report SDQ and the clinical sample received formal diagnoses from a child psychiatrist blind to SDQ scores. The discriminative validity of the SDQ was investigated using Receiver Operator Characteristic (ROC) curves and by assessing Area Under the Curve (AUC). RESULTS: The SDQ discriminated reliably between clinical and community samples for the SDQ total score and its subscales. Within the clinic sample, 49 % of patients qualified for more than one broad diagnostic grouping. The SDQ discriminated between diagnostic categories in the clinic sample, but did so most effectively for conduct disorders. Based on the cut-offs that generated the highest combined value of sensitivity and specificity, the estimated rate of psychiatric disorder in the community sample was 13.6 % (parent-report) and 7.3 % (self-report). CONCLUSIONS: The SDQ is a useful screening tool for child and adolescent mental disorders for Malayalam speakers in Kerala, India.