BACKGROUND AND AIMS: Time trends in major cardiovascular risk factors are described in cohorts of middle-aged men followed for 35 years in 9 European cohorts of Finland, The Netherlands, Italy, Serbia and Greece. METHODS: Men aged 40 to 59 years at entry in the early 1960s were repeatedly re-examined 3 to 5 times over the last 35 years. Systolic blood pressure, serum cholesterol, body weight and body mass index were considered for analysis, including study of aging (35 years of follow-up) and of generation effects (10 years for men aged 50-59 in the period 1960-1970 and separately 10 years for men aged 75-84 years in the period 1985-1995). RESULTS: For the aging effect, average systolic blood pressure increased approximately 15 mmHg over 25 years maintaining a steady state thereafter, the largest increases being found in Serbia and Greece. Average serum cholesterol varied between approximately 4.5 in Serbia and 6.5 mmo/L in Finland in about 1960. Twenty-five years later, the average level was about 6 mmol/L in all five countries and decreased slightly thereafter. Average body weight and body mass index increased in all countries for 25 years and levelled off thereafter. For the generation effect, average systolic blood pressure decreased in all countries, with the exception of men aged 50-59 in Serbia and men aged 75-84 in The Netherlands. Average serum cholesterol uniformly increased in men aged 50-59 for the younger age-class and slightly decreased in men aged 75-84. Average body weight and body mass index increased systematically in all countries and in both age groups. CONCLUSIONS: Major changes were the great increases in average systolic blood pressure and serum cholesterol level in Serbia and in systolic blood pressure level in Greece between 1960 and 1985, and the large decrease in average serum cholesterol in Finland between 1970 and 1995. Average body weight and body mass index showed universal increases in both middle-aged and older men after 1960.