Coagulation activation markers are being investigated as risk factors for cardiovascular disease; we examined the contribution of several lifestyle factors to variation in plasma levels of several activation markers measured in a population-based study of 1947 men. Smoking, alcohol, body mass index (BMI), leisure and work activity, social class, and use of prescribed medicines were each examined in turn. Specific assays of fibrin D-dimer and von Willebrand factor (vWF) activity showed similar relationships to lifestyle variables as we observed previously for less specific assays of D-dimer and vWF antigen. D-dimer levels increased with age, in smokers and in men taking prescribed medication, and were negatively associated with leisure time activity. vWF activity increased with age and showed a U-shaped distribution with BMI. Factors VIIc and VIIIc and thrombin-antithrombin complexes were associated with BMI, factor VIIIc and prothrombin fragments 1 + 2 (F1 + 2) were associated with age, activated partial thromboplastin time (aPTT) and F1 + 2 were associated with smoking, and aPTT showed a small negative association with alcohol consumption. We conclude that lifestyle modification has the possibility of favourably influencing several of these risk markers. In particular, cigarette smoking has a possibly reversible effect on coagulation activation (measured by F1 + 2 and D-dimer).