The relationship between cardiovascular responses to stress and health outcomes is inconsistent. In this study, the effects of morningness-eveningness and time of day upon cardiovascular activity at rest and in response to stress were examined. Sixty morning-types and evening-types completed two testing sessions (one morning, one afternoon) that comprised a battery of three stress tasks and a measure of anxiety. The results failed to support a time of day effect upon cardiovascular activity, but there was evidence of an interaction between time of day and morningness-eveningness upon heart rate (HR) and rate pressure product (RPP; HRxSBP). Evening-types exhibited higher HR and RPP in the afternoon, both at rest and during stress. A time of day effect was shown for mood, with anxiety levels higher in the morning than the afternoon. These results are discussed in terms of their health and methodological implications.