Understanding moderators of acute responses to stress has implications for a variety of outcomes in health psychology. The present study investigated the role of sustained search for potential threat in acute cardiovascular stress responses. As a means of manipulating vigilance for threat in the laboratory, male participants (N = 30) were randomly assigned to search, on a computer screen, for statements that were negative, positive, or occurring at known intervals. Relative to participants in the other search conditions, participants in the negative search condition had significantly higher systolic and diastolic blood pressure responses during subsequent stressors. These results encourage a closer look at the effects of vigilance for threat.