BACKGROUND AND OBJECTIVE:To evaluate the trend in the prevalence in Spain of obesity, diabetes mellitus, hypertension and hypercholesterolemia. MATERIAL AND METHOD:The Spanish National Health Surveys (ENS) of 1997, 2001, 2003, which select representative samples of the Spanish general population were used. In total, 49,113 participants of both sexes were included. Self-reported data about weight and height were used to estimate the body mass index. The prevalence of diabetes, hypertension and hypercholesterolemia was estimated. Linear trend chi2 tests and multivariate logistic regression models adjusted for age, sex and educational level, were estimated. RESULTS:A significant increasing temporal trend for the prevalence of obesity, diabetes, hypertension and hypercholesterolemia was found for the studied period (1997-2003) according to the ENS. We found that the increased trend in obesity prevalence was restricted to younger participants with a significant interaction. CONCLUSIONS:The prevalence of obesity, diabetes mellitus, hypertension and hypercholesterolemia has increased in Spain between 1997 and 2003.