Background: Body Mass Index (BMI) is simple measure of the weight of a person scaled according to their height. On the other hand Body Fat Percentage (PBF) is the weight of a person’s fat divided by the person’s weight. BMI is widely used method for estimating body fat mass. It is an accurate reflection of Body Fat Percentage (PBF) in the majority of the adult population.

Methods: The aim of this study was to investigate the relationship between Body Mass Index & Body Fat Percentage among the adults Tai Ahom Population of North Lakhimpur district of Assam. A cross-sectional study was conducted among 850 adult populations, out of which 411 males and 429 females from the age group 20 years to 60 & above years were participated.

Results: Pearson’s correlation coefficient (r) was calculated to see the relationship between BMI- BF % in the different age groups. A significant positive correlation was observed between BMI-BF% in males (r=0.75, p<0.01) and in females (r=0.68, p<0.01).

Conclusion: The study shows strongly correlated BMI with BF% estimated by bioelectrical impedance, in this Tai Ahom group of population. This relationship was significantly influenced by age and BMI. The present study supports the importance of taking age and BMI in to consideration to predict body fat percentage in a population.