Measurements of blood pressure in 52,064 men and women in the city of Bergen, Norway, who were 30 to 89 years in 1963, have been related to mortality occurring in different intervals of the follow-up period from 1963 throughout 1983. Blood pressure measurements obtained on one occasion were highly predictive of both coronary heart disease, stroke and all-cause mortality several years after measurements. The relative risk of stroke mortality associated with blood pressure varied little in the first ten to fifteen years, but the predictive power was clearly lower in the last five years of follow-up. The relative risk of death from coronary heart disease was stable in the whole period of follow-up. The risk curves relating coronary heart disease mortality to diastolic blood pressure in men and women aged 60-79 years at screening had the same shape in the first five years as in the rest of the follow-up. No J-shaped association was seen in either time interval.