BACKGROUND: The goals of the present report are to assess the differences in distribution of traditional coronary risk factors in a work setting, aimed at identifying specific groups at risk and to compare mean values of such risk factors and of an overall risk score of the entire working sample with the results observed in the third WHO-MONICA population survey carried out in northern Italy (Area Brianza). METHODS: In the SEMM study 7872 employees (2601 men and 5271 women) were enrolled between 1992 and 1996. The third MONICA survey in Brianza was carried out on an age- and gender-stratified random sample of 831 men and 884 women in 1993-1994, selected from the 25-64-year-old residents of five municipalities, representative of the study population. In both studies coronary risk factors were measured according to the MONICA protocol, adopting standardized methods. RESULTS: In comparison with the MONICA population sample, the entire working group showed lower mean levels of blood pressure and total cholesterol, higher prevalence of current cigarette smokers and lower mean levels of HDL cholesterol, in both gender groups. Prevalence of overweight subjects was higher among men in the working group, but the opposite pattern was detected in women. The overall risk score, calculated using the coefficients of a proportional hazard survival equation estimated in a large collaborative Italian follow-up study, resulted lower in the working sample, in both gender groups. This result may be attributed to a selection bias known in occupational epidemiology as "healthy worker effect". In contrast to this finding, the prevalence of smokers, in particular among women, was higher in the employed sample, indicating that working stress conditions may play some role. CONCLUSIONS: In order to extend the assessment of cardiovascular risk factors as well as prevention activities in work settings, some advantages are highlighted: the high participation rates, the feasibility to adopt standardized protocols, and easier and cheap procedures for censoring in follow-up studies. Moreover, due to the recently adopted legislation in Italy which increases the number of working categories to be included in periodic clinical examinations, prevention activities in work settings to contrast the epidemic of widespread chronic diseases, like cardiovascular diseases, are encouraged. This will also allow for the investigation of individual variations over time of coronary risk factors.