This article provides an overview of work in two areas of biobehavioural research: the effects of environmental stress and the role of psychophysiologic reactivity in the development of ischaemic heart disease. Attention is given first to evidence that low socio-economic status, low social support, and occupational settings characterized by high demands and low levels of control over the job are associated with increased coronary risk. Also discussed is a promising animal primate model of social stress and its role in development of coronary atherosclerosis. Next, we discuss physiological responsiveness (reactivity) to emotional stress, which is being studied as a marker of processes involved in the development of cardiovascular disease. Stress and psychophysiological reactivity constitute promising targets for research on biobehavioural antecedents of coronary disease and for clinical intervention studies. However, further evidence is needed before these variables can be regarded as proven coronary risk factors.