Although startle and cardiovascular reactivity have been studied extensively, little is known about their relationship. In the present study, we examined cardiovascular responses and affective startle modulation in 112 normotensive individuals varying in self-reported fearfulness and parental cardiovascular health history. An initial intense noise burst elicited a phasic cardiac acceleration that was larger for fearful individuals. Startle blink responses were larger during aversive than during pleasant relaxing imagery but did not differ with fear group. Cognitive challenge tasks elicited heart rate and blood pressure increases that were unrelated to fearfulness or parental health history. However, greater startle potentiation by aversive imagery predicted larger pressor responses to cognitive challenge, especially among men. The observed relationship between startle and cardiovascular reactivity suggests a common mechanism for their affective modulation.