Out of a group of persons who had had mild hypertension (170/100 mmHg) at the age of 14--29 in the years 1952--1954, 72% were re-examined after 20 years. A surprisingly large part of them (36.3%) had a normal blood pressure even without any treatment during last 15 years. In 43.4%, the hypertension is now stabilized, and in 20.3% a progression of hypertension was found. The prognosis of a mild juvenile hypertension is significantly related to the family history of hypertension, the longevity of parents, and to the initial level of blood pressure.