The present paper describes the development of a scale to measure emotional reactivity. The Emotional Assessment Scale (EAS) consists of 24 emotion descriptors. Subjects rated the intensity of emotion on a 10-cm visual analogue scale. The first study evaluated psychometric properties of the scale by administering the EAS, Profile of Mood States, State-Trait Anxiety Inventory, and Beck Depression Inventory to 120 college students. Reliability and validity of the EAS met established guidelines. The second study provided data on emotional reactivity to laboratory Stressors. Three samples were included: college students, hospital employees, and men with a family history of cardiovascular disease. In each sample, emotions were assessed using the EAS at three phases: baseline, mental arithmetic (MA), and cold pressor (CP). Overall, the three samples showed similar emotional responses to the laboratory Stressors. There was a general trend for increases in negative emotion to both tasks, with more emotional responses to MA as compared to CP. These data are discussed in terms of the usefulness of the EAS for measuring momentary changes in emotion in laboratory or clinical settings.