Life expectancy is higher in Japan than in the United States. We compared the prevalence of clinically recognized risk factors in the two countries to explore the possibility that differences in these likely precursors to disease and death are linked to the paths to higher mortality for Americans. We found that American men and women have higher levels of total biological risk than the Japanese, particularly for risk factors included in the metabolic syndrome. A significant difference between the two countries is the higher prevalence of overweight among Americans. On the other hand, measured blood pressure appears more favorable among Americans. A larger proportion of Americans use prescription drugs, which results in lowered levels of measured biological risk. There are large differences in the prevalence of a number of risk factors between American and Japanese women less than age 40; this could mean that Americans develop biological risk earlier in life or that the differences are growing larger in more recent cohorts.