Obesity is a serious health problem in developed countries. Knowledge of reliable and nationwide representative data is a must for any public health action. The dimension of this problem in Portugal was first assessed in 1995-1998. A similar populational survey using objective anthropometric measures is now being conducted (field work started in January 2003). A total of 6411 subjects aged 18-64 years old have already been measured and their respective body mass indexes (BMIs) calculated. Results from 2003 to 2005 show 38.6% is overweight and 13.8% has obesity. The total of overweight and obesity is 52.4%. In 1995-1998 survey, overweight was 35.2% and obesity was 14.4%. The total was 49.6%. These results suggest an increase of the overweight/obesity (altogether) prevalence in the last 10 years. Actual results show that more than half of the adult sample has excessive weight and 2.4% of the sample has low BMI. Finally, 45.6% of the sample suffers increased health risks because of high waist circumference (> or =80 cm for women; > or =94 cm for men). These results highlight the fact that, although obesity was identified as a public health problem one decade ago, action to reduce it does not seem to have been very effective to date.