The purpose of this study was to assess by analysis of published controlled trials the efficacy of cognitive behavioral therapies (such as biofeedback, relaxation, and meditation) for essential hypertension. From among 800 studies published in the English language between 1970 and 1991, only 26 met the suitability criteria for entry into this meta-analytic study. In 16 comparisons involving baseline blood pressure periods of more than one day, with patients (n = 368) assigned to either a cognitive therapy or a placebo intervention (sham biofeedback, "pseudomeditation"), systolic and diastolic blood pressures decreased by 2.8 mm Hg and 1.3 mm Hg, respectively. These changes were neither statistically nor clinically significant. The authors concluded that cognitive interventions for essential hypertension are superior to no therapy but not superior to credible sham techniques or to self-monitoring alone. They identify several methodological inadequacies in the literature that limit the interpretation of the findings. No single cognitive behavioral technique appears to be more effective than any other.