Trends of cardiovascular disease risk factors were evaluated through comparison of three national surveys in Japan, 1971-1990. Data from three Japanese national surveys on circulatory disorders, conducted in 1971, 1980, and 1990, were analyzed. Variables common to the three national surveys were selected for analysis. Serum total cholesterol was also but was examined only in 1980 and 1990. Age- and sex-specific mean values, standard deviations, median values, and proportions in extreme categories were determined for all continuous variables and proportions in categories interest for all discrete variables. Trends from 1971-1990 and 1980-1990 were estimated by linear regression analysis for continuous variables, and logistic regression analysis for binary variables. Systolic blood pressure was decreasing constantly during three surveys in both men and women (beta = -0.22 in men and -0.34 in women, p < 0.01 in both). Total cholesterol was increasing rapidly in both men and women between 1980 and 1990 (beta = 1.27 in men and 1.41 in women, p < 0.01 in both). For other risk factors, the results were less consistent among age- or sex-specific groups. Continued monitoring of risk factor trends in Japan will be important for predicting and explaining future trends in the occurrence of coronary heart disease and stroke in this population.