Paffenbarger, R. S., Jr. (Calif. State Dept. of Public Health, Berkeley, Calif. 94704) and A. L. Wing. Chronic disease in former college students. XI. Early precursors of nonfatal stroke. Amer J Epidem 94: 524–530, 1971.—Doctor-diagnosed stroke was reported by 102 of 10, 327 men who had attended Harvard University, 1916–1940, and who had returned a usable, self-administered mail questionnaire in 1966. A 67% response was achieved from a single mailing and the reliability and validity of answers were found to be generally acceptable. The mean age of subjects was 54 years at time of stroke occurrence, while the mean age of respondents ranged from 64 for the five earliest college classes to 47 for the five most recent classes. Examination of university medical records of these former students revealed four characteristics in youth that predisposed to increased incidence of nonfatal stroke in later life: higher levels of blood pressure, increased weight for height, shorter body stature, and cigarette smoking. Paired combinations of any of the four characteristics had an additive or greater effect on stroke incidence. Similarly, questionnaire responses in 1966 from these former students revealed four high risk characteristics that associated with an increased prevalence of nonfatal stroke: high blood pressure, coronary heart disease, diabetes, and a history of parental hypertension. High blood pressure exerted the strongest influence on prevalence of nonfatal stroke, both singly and when paired with the three other characteristics. High blood pressure in the former students and a history of parental high blood pressure, both determined by questionnaire, were each better predictors of nonfatal stroke than higher levels of blood pressure assessed in college.