Background: The main aim of this study was to the determine relationship between BMI and BF% in Singaporean adults, derive a prediction model to estimate BF%, and to report population BF%. The secondary aim was to determine the prevalence of overweight and obesity based on BF% threshold and the new risk categories for obesity in Singaporean population.Methods: This was a population-based study of 542 community-dwelling Singaporeans (21-90 years old, 43.1% men). Anthropometry and body composition were assessed. Relationship between BMI and BF% were analysed using multiple regression model. Prevalence of overweight and obesity were estimated using WHO and Singapore Ministry of Health (MOH) Clinical Practice Guidelines BMI classification, and BF% cut-off points of 25% and 35% for men and women respectively. Results: We derived a prediction model to estimate BF% based on BMI, age, sex and ethnicity. The current cohort of Singaporeans have higher BF% at matching BMI, age and sex than Caucasians in the US and Europe, and a Singaporean cohort from 20 years ago. The overall population-adjusted prevalence of obesity according to WHO International classification (BMI ³30kg/m2) was 12.9% (14.9% men; 11.0% women); and 26.6% (30.7% men; 22.8% women) according to MOH classification (BMI ³27.5kg/m2). However, using BF% cut-off (>25% for men and >35% for women) resulted in very high prevalence of obesity of 82.0% (80.2% men; 83.8% women).Conclusion: There is a large discrepancy between BF% and BMI measured obesity in Singaporean adults. The results confirmed that Singaporean adults have higher BF% at lower BMI compared to US and UK white counterparts; and that BF% in our population have increased over two decades.