This study investigated the effects of task demand (absence or presence of time pressure) and decision latitude (choice or no choice over a task) on cardiovascular and affective responses to stressful tasks among 70 college students. Subjects also rated whether they felt under pressure and the extent to which they felt in control. Time pressure was related to elevated systolic blood pressure (SBP) responses among men and increased negative affect for both sexes. Lack of choice over the task also resulted in increased negative affect in both sexes. The least stressful condition--having a choice in the absence of time pressure--resulted in reduced negative affect. In addition to the effects of manipulated decision latitude and demand, perceptions of being in control were associated with reduced SBP among women who had a choice. Perceived control also contributed to reduced negative affect among men. These results suggest that the postulated negative effects of high demand and low decision latitude (ie, job strain) on cardiovascular health may be mediated in part by increased cardiovascular reactivity and negative affect.