Current clinical diagnostic procedures may lead to an V over-identification of hypertension. The lack of a comprehensive assessment may also lead to difficulty in timing cognitive-behavioral interventions to coincide with periods when blood pressure is most elevated. The goals of the current study were (a) to determine if a laboratory relaxation procedure would be capable of discriminating those individuals who generally have elevated blood pressure from those who react with increased blood pressure specifically to laboratory assessment, and (b) to identify "markers" of emotional states which would enable individuals to determine when their blood pressure was elevated. Fifty-one undergraduate students at Virginia Tech volunteered to participate in a two-hour laboratory session consisting of baseline blood pressure measurements, a relaxation procedure and a battery of psychological questionnaires assessing anger, anxiety and Type A. This was followed by a two-day self-monitoring period consisting of approximately twelve self-reports of mood state concurrent with blood pressure measured by a portable, semi-automatic monitor. Results suggested that blood pressure response to the laboratory relaxation procedure was associated with the difference between average ambulatory blood pressure and laboratory blood pressure for diastolic A blood pressure only. Anger arousal and anger expression were unrelated to either average ambulatory blood pressure or high versus low ambulatory blood pressure readings. Perceptions of the environment as hostile and demanding did discriminate between high versus low systolic blood pressure and diastolic blood pressure readings. A cluster of negative moods discriminated between high and low systolic blood pressure readings. A cluster of moods characteristic of the Type A behavior pattern also discriminated high versus low systolic blood pressure readings as well as high versus low heart rate readings. One of the clearest findings of the study was the relationship between the type of analysis used and the probability of finding an association between psychological variables and blood pressure. In general, across subject analysis yielded fewer significant relationships than analyses emphasizing within subject variation. Exploring this further, two case studies are presented which illustrate statistical procedures for analyzing the relationship between blood pressure and mood in single case designs. / Ph. D.