To examine population mean variations in plasma fibrinogen and fibrinolytic variables, and their rela tions with cardiovascular risk characteristics among Japanese middle-aged men, a cross-sectional study was conducted for a total of 245 men aged 50-59 years in three population-based samples: residents in rural communities of northeast and central Japan and urban white-collar workers. Age-adjusted mean value of plasma fibrinogen, tissue plasminogen activator antigen (t-PA antigen), plasminogen activator inhibitor 1 antigen (PAI-1 antigen) did not differ significantly among the populations. Mean value of tissue plasminogen activator activity (t-PA activity) was lower in central rural residents than in northeast rural men. According to multiple linear regression analyses, there were positive associations of t-PA and PAI-1 antigens with serum triglyceride levels, serum insulin and waist-hip ratio within each population and the total samples. A positive association between these fibrinolytic variables and usual ethanol intake was also observed. Smoking was significantly associated with plasma fibrinogen and PAI-1 antigen but not with t-PA antigen or activity. Activity of t-PA was inversely associated with body mass index, and a mean difference in t-PA activity was in part explained by a mean difference in body mass index. In conclusion, population mean values of plasma fibrinogen and fibrinolytic variables did not differ among three Japanese populations except for mean t-PA activity. Reduced fibrinolysis expressed as increased PAI-1 antigen was associated with smoking and the status of insulin resistance, such as high levels of serum insulin, serum triglycerides and waist-hip ratio.