To document the prevalence of obesity in Saudi Arabia, we used data from a cross-sectional study on 19,598 individuals in 2837 households. Body mass index, skinfold thickness and mid-arm circumference were measured. Prevalence of obesity ranged from 33.9% in Ha'il to 11.7% in Jizan. More women than men were obese, 23.6% compared to 14.2%. Prevalence of overweight was 30.7% for males and 28.4% for females. Obesity was present in all age groups. It is clear that changes must be made to the lifestyle of the Saudi population in order to reduce the prevalence of obesity.