To assess the prevalence of thinness among 2-5 years pre-school children, a cross-sectional study was conducted among 284 pre-school children (Boys-144; Girls-140) of Kolam tribe. Kolam, a primitive tribal group predominantly lives in Utnoor, Narnoor and Jainoor mandal (s) of Adilabad district, Telangana, India. Anthropometric measurements like height and weight were used to compute body mass index following standard techniques. The new international classification cut-off points provided for boys and girls aged 2 years to 5 years were used to identify the prevalence of under nutrition. It was observed that the participants of both the sexes showed a marked difference in body weight. The overall prevalence of thinness was 72.91% for Kolam boys and 72.14% for Kolam girls indicating that children of both the sexes were undernourished.