This paper presents an analysis of self-reported stressors and blood pressure in a population of 1,428 San Francisco bus drivers surveyed from 1983 to 1985 as part of an occupational health study. To test the hypothesis of a positive association between psychosocial stressors and hypertension, the authors derived a stressor index from a survey instrument that assessed subjects' appraisal of work-related problems. A logistic regression analysis revealed an unexpected inverse association between the stressor index and hypertension that remained significant after adjustment for 12 potential confounding variables (standardized odds ratio = 0.84, p = 0.038). An analysis restricted to the 1,040 normotensive subjects, with mean blood pressure level as the outcome variable, also yielded inverse findings. To assess whether the results were specific to blood pressure, the authors repeated the multiple logistic analysis for gastrointestinal, respiratory, and musculoskeletal problems. In contrast to the inverse association found for hypertension, highly significant positive associations were found between the stressor index and these health problems. When prevalence of disease was examined by level of stressor score, a significant inverse gradient was observed for hypertension and significant positive gradients were observed for gastrointestinal, respiratory, and musculoskeletal problems (p values less than 0.001). An etiologic implication of these findings is that there may be a direct inverse association between subjective appraisal of stressors and blood pressure. A methodological implication is that subjective appraisal of stressors by persons with heightened blood pressure may be an invalid measure of objective, verifiable stressors.