The impact of most, but not all, cardiovascular risk factors decline by age. We investigated how the metabolic syndrome (MetS) was related to cardiovascular disease (CVD) during 40 years follow-up in the Uppsala Longitudinal Study of Adult Men (ULSAM, 2,123 men all aged 50 at baseline with reinvestigations at age 60, 70, 77 and 82). The strength of MetS as a risk factor of incident combined end-point of three outcomes (CVD) declined with ageing, as well as for myocardial infarction, ischemic stroke and heart failure when analysed separately. For CVD, the risk ratio declined from 2.77 (95% CI 1.90-4.05) at age 50 to 1.30 (95% CI 1.05-1.60) at age 82. In conclusion, the strength of MetS as a risk factor of incident CVD declined with age. Since MetS was significantly related to incident CVD also at old age, our findings suggest that the occurrence of MetS in the elderly should not be regarded as innocent. However, since our data were derived in an observational study, any impact of MetS in the elderly needs to be verified in a randomized clinical intervention trial.