This study extends previous work investigating the generalizability of cardiovascular reactivity to stress obtained in response to laboratory-based tasks to cardiovascular reactivity measured in response to a naturally occurring event. Heart rate (HR) and blood pressure reactivity to stress were measured with ambulatory monitoring equipment in 6 male and 16 female healthy, White, graduate students in two settings: during five standardized stressors in the laboratory, and during the proposal or defense of a thesis or dissertation. Results indicate that for all cardiovascular parameters, the magnitude of change was greatest in response to the natural event, and that among the laboratory tasks, the greatest degree of reactivity was observed in response to a speech task. However, the cardiovascular reactivity associated with the speech task was not the best predictor of the natural speech task, despite the structural similarity of these two tasks. Overall, greater correlations were noted among all of the tasks based on absolute values of HR and blood pressure versus residualized change scores for HR and blood pressure, and greater correlations also were observed among anticipation periods than among task periods. Partial support was provided for the hypothesis that the generalizability of cardiovascular reactivity to stress would be enhanced by using multiple laboratory tasks rather than single tasks. This effect was observed for HR but not blood pressure. Consistent with the literature in this field, we observed only limited generalizability of cardiovascular response to stress from laboratory to the field.