Differences in blood pressure associated with reported happiness, anger, and anxiety are examined among 90 borderline hypertensives during 24-hr blood pressure monitoring. There were 1152 individual ambulatory blood pressure readings for which subjects classified their emotional state as happy (n = 628), angry (n = 67), or anxious (n = 457) on scales from one (low) to ten (high). Pressures were transformed to z-scores using the subject's 24-hr mean and standard deviation to assess relative elevation during reported emotional arousal. The results show that emotional arousal significantly increases systolic and diastolic pressure (p less than 0.00001), an effect independent of posture and location of subject during measurement (at work, home, or elsewhere). On average, pressures during reported angry or anxious states were higher than those during a happy state (p less than 0.01). Examination of arousal intensity showed that scores on the happiness scale were inversely related to systolic pressure (p less than 0.01) whereas the degree of anxiety was positively associated with diastolic pressure (p less than 0.02). Emotional effects were also related to the degree of individual daily pressure variation such that the greater the variability, the larger the blood pressure change associated with the emotions. The results suggest that happiness, anger, and anxiety increase blood pressure to differing degrees and that emotional effects may be greater in individuals with more labile blood pressure.