Objective: To carry out a cross-cultural translation and adaptation of the Child-OIDP instrument and to assess its reliability and validity among 11-12 year olds in Karnataka, South India. Methods: The original Child-OIDP was obtained from the author, cross-culturally adapted to the Kannada language then the translation’s content, face criterion and construct validity and internal and external reliability were evaluated. Children recorded their oral health problems and rated their oral health in a cross sectional study of 505, 11-12 year olds selected from a list of Karnataka schools by using simple random sampling (89.7% participation rate). Results: The child OIDP revealed good validity and reliability. In relation to construct validity; an exploratory factor analysis provided two factors with eigenvalues greater than 1, which represented the physical and psychosocial health components. Cronbach’s alpha was 0.60 and test–retest reliability, 0.85 (intra-class correlation coefficient). Conclusions: The Kannada Child-OIDP is a valid and reliable interviewer-administered instrument to measure the impact of the oral conditions on quality of life in children in Karnataka, South India. Key words: child–OIDP, cross-cultural adaptation, reliability, validity