The metabolic syndrome is likely to develop in patients in whom genetic predisposition, chronic stress, negative emotion, and unhealthy lifestyle habits converge. In light of the psychophysiologic aspect of most of these factors, biofeedback, relaxation, and other psychophysiologic interventions have been studied and used in patients with elements of the metabolic syndrome, particularly diabetes and hypertension. This article reviews the rationale and evidence for biofeedback for the treatment of diabetes and hypertension, which has been shown to effectively lower blood glucose and blood pressure in numerous studies. Patients with prehypertension may be a particularly appropriate target population for biofeedback for blood pressure reduction. Further research is needed to guide identification of the best candidates for psychophysiologic intervention for these conditions, although patient readiness for change is a clear prerequisite.