Background This study was carried out in order to examine changes in cardiovascular risk associated with a population-based screening programme. Method Cardiovascular disease (CVD) risk factor data from a representative sample of residents aged between 45 and 55 years who attended screening a total of three times over a 10-year period were chosen for analysis (n = 4113). Cohorts were defined as either 'high risk' or 'normal risk' at baseline for risk factors including blood pressure, body mass index (BMI), cholesterol, smoking and alcohol Intake. Mean changes were observed for both groups over three screening episodes, and results were stratified by gender. Results For the high-risk cohorts (after controlling for age and regression to the mean effects), there were significant decreases In all risk factors, except BMI. Conversely, the observed changes in the normal risk cohorts indicated significant Increases In risk factors over the 10-year period. After adjusting for age, the pattern In the normal risk cohorts fluctuated and there were some decreases in risk, but they were not as large as the decreases In risk for the high-risk cohorts. Conclusions Population screening for CVD is an effective strategy for identifying and reducing risk In high-risk individuals. These results have significant implications for the role of screening in preventing and controlling cardiovascular disease.