10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 1 2016 (January - March) Vitamin D deficiency is a pandemic health problem and a risk factor for the development of impaired glucose tolerance in childhood obesity. The aim of the study is to determine the relationship between 25- hydroxy vitamin-D levels and insulin resistance in obese and non obese patients. The study group included 50 obese and 50 non obese adolescents aged 16-18 years. Anthropometric data were collected and fasting serum glucose, insulin and 25-(OH) D was measured. The homeostatic model assessment of insulin resistance was calculated in both groups. The levels of 25-(OH) D in obese group were significantly lower and (p lessThan 0.001) HOMA-IR were significantly higher than non obese adolescents (p lessThan 0.001). The mean fasting insulin levels in obese adolescents were found to be lower than non obese adolescents. In the obese group vitamin D and insulin showed a positive correlation with insulin resistance. The finding suggests that insulin resistance plays a major role in obesity than vitamin D levels. DR. MEERA SHIVASHEKAR DR. M. VASANTHA AND SARGURU. D 25- hydroxy vitamin D, HOMA-IR, BMR. 488-490