The effects of salt loading on the cardiovascular response to mental stress was compared between 8 adolescents with high genetic risk (Genetic group) for essential hypertension (hypertensive parents) and 8 adolescents with low risk (Control group) (normotensive parent). Systolic (S), Diastolic (D) pressure and heart rate (HR) were monitored (Arteriosonde) at 1 minute intervals during difficult mental arithmetic. Plasma catecholamines (CA) were determined before and after stress. Subjects then consumed 10gm/day Na Cl in excess of usual diet for 14 days. Mental stress and CA were then repeated. Measurement of urine Na confirmed high salt intake. A greater cardiovascular response (greater increase in S, D, and HR) was seen in Genetic group compared to Control (p < .01). Salt loading increased BP, augmented the high D responses and suppressed CA in the Genetic group. Salt loading produced no change in BP or CA in Controls. Concl: Genetic adolescents have a higher cardiovascular response to mental stress. Some genetic adolescents are salt sensitive. Control adolescents are salt resistant.