Two Swiss regions, the cantons of Vaud and Fribourg (VD-FR) and the canton of Ticino (TI), take part in the international research project MONICA (MONItoring trends and determinants in CArdiovascular disease). In this framework, three surveys are planned to monitor the prevalence of the principal risk factors. The second survey was carried out in 1988/89 on 2011 participants aged 25 to 74 for the VD-FR region and on 1458 participants aged 35 to 64 for the TI region. This article is devoted to the results concerning smoking habits, blood pressure, body height and weight. In the VD-FR region, the percentage of regular smokers steadily decreases with age, from 44% for men and 36% for women in the 25-34 age group to 15% and 10% respectively in the 65-74 age group. Inversely, the proportion of participants with high blood pressure rises steeply with age from nearly zero in the 25-34 group to more than a quarter in the 65-74 group. Similar risk factor levels are observed in the TI region. Two significant trends show up in comparison with the first survey (1984-86) for the latter region: the decreases in mean blood pressure levels for both sexes and in the proportion of regular smokers for men. However, these trends are to be interpreted cautiously because of potential measurement bias between surveys.