Maximum likelihood method with probit transformation was applied to estimate median age at which chest circumference (CC) overtook head circumference (HC) in 1206 children from rural areas of Ballabhgarh in Haryana and in 1505 children from a slum population in Delhi. The results showed that, in case of rural area, this phenomenon occurred at an average age of 31.36 months and in children from urban slums, at an average age of 28 months. In both the areas, this phenomenon occurred at an average age of 20 to 21 months in normally nourished children. In children with grade I malnutrition, this was delayed by about 10 months as compared to those with normal nutrition and in children with grade II or worse malnutrition, this was further delayed by another 9 to 13 months on an average as compared to those with grade I malnutrition. These differences were found to be statistically significant (p < 0.001). These results indicate that the longer the delay in CC overtaking HC, the chance is higher for the children to be severely malnourished. Considering the relative ease of measuring head and chest circumferences, this parameter (age of CC crossing HC) could be useful in assessing the long term trend in the improvement of childhood nutrition in developing countries.