Blood pressure and heart rate reactions of 182 confirmed offspring of normotensive (110 female, 72 male) and 112 offspring of hypertensive (66 female, 46 male) individuals to the stressor of blood donation were examined. Subjects were tested at two sites, one in the United States and one in Canada. Although influenced by site, young normotensive offspring of hypertensives generally exhibited significantly greater blood pressure levels in anticipation of donating blood than offspring of normotensives. The higher reactivity of offspring of hypertensives observed in stressful laboratory settings may generalize to more ecologically valid settings, even those which, like blood donation, require passive coping efforts.