A multicentric cross-sectional collaborative study was undertaken in 3 centres in India with the main aim of developing simple and reliable indicators for the early detection of developmental disabilities in children under 6 years of age and to compare the age of attainment of developmental milestones in children in the three regions. The study provided a simple low-cost and culture-appropriate psychosocial developmental screening test battery which can be used with ease by trained public health grass-roots functionaries. This instrument was standardized on a large rural, tribal and urban sample comprising more than 13,000 children from 3 regions in India. The procedure for sampling, selection of items and methodology for standardization of the instrument in the Hyderabad region detailed in this paper were replicated in other centres as well. Quality control of data was ensured through inter-rater and test-retest measures of reliability. During pre-testing, 66 culture-appropriate milestones were selected finally from a larger item pool. The 50th centile age reference values of the Hyderabad study children and those obtained by other 2 centres were comparable.