Background: High ambulatory blood pressure (ABP) predicts cardiovascular events, even after controlling for clinic BP and other established risk factors. Purpose: This study examined whether chronic or discrete stress in thepastyear was associated with greater ABP in adolescents. Method: Participants were 217 male and female Black and White adolescents who wore ABP monitors on 2 consecutive school days and completed a survey of life events. Results: Report of discrete, negative events was not associated with ABP. Adolescents experiencing greater numbers of chronic, negative life events exhibited greater systolic blood pressure (SBP), independent of ethnicity; sex; body mass index; and location, position, physical activity, and consumption of food/caffeine/nicotine at time of measurement. Greater numbers of chronic, negative events were associated with greater diastolic blood pressure (DBP) among boys. When resting clinic BP was introduced into the model, the main effect of chronic, negative life events on ambulatory SBP became nonsignificant, whereas the effect of chronic, negative life events on male adolescents' DBP persisted. Conclusions: Chronic stress is associated with greater ambulatory SBP among male and female adolescents and with greater ambulatory DBP among male adolescents. The latter association persisted after controlling for clinic BP, suggesting that males may be more vulnerable to chronic stress as a determinant of BP regulation than females early in life.