The nutritional status of infants is assessed using the WHO growth references, based on the Multicenter Growth Reference Study (MGRS) in many countries including Sri Lanka. Birth parameters define infant growth curves. The aim of this study was to compare the birth anthropometric data of a healthy population of babies born in Colombo, Sri Lanka with the WHO MGRS birth data and determine its suitability for assessment of growth in this population. Birth data were obtained as part of a study on longitudinal infant body composition from birth to 2 years from 2015-2019. Healthy babies, born to non-smoking mothers, >18 years old, with a singleton pregnancy at term, living in the study area and intending to breastfeed, were recruited. The Ethical Review Committee of the Faculty of Medicine, University of Colombo, approved the study. Compared to WHO data, the mean birth weight (2.9±0.4 kg), length (48.2±2.7 cm) and head circumference (33.6±1.2 cm) of our study population (n=337) was significantly lower with a left shift in the z score distribution. This was despite similar background characteristics except for significantly lower income (USD 200) and lower maternal (154.2±9.0 cm) and paternal height (165±11.6 cm) in our study population. A significant change in birth parameters was only seen with maternal height when disaggregated. WHO birth parameters were significantly higher and underestimated the growth of healthy babies in Sri Lanka.