Congestive heart failure is characterized by decreased parasympathetic and increased sympathetic nervous system activity. Impairment of baroreceptor reflex function may be relevant to this altered neural profile. The effect of cardiopulmonary and arterial baroreceptor stimulation on corresponding afferent neural activity is reduced in experimental models of heart failure. In addition, the heart rate and blood pressure responses to perturbations in arterial and carotid sinus pressure are less in animals with heart failure than in control animals. Comparable observations have been made in humans. Unloading cardiopulmonary baroreceptors with lower-body negative pressure causes less forearm vasoconstriction in patients with heart failure than in healthy subjects. The chronotropic response to changes in arterial and carotid sinus pressure induced by drug infusions or by use of a neck chamber is attenuated in heart failure. These data suggest that abnormalities in cardiopulmonary and arterial baroreceptor reflex function contribute importantly to altered autonomic nervous system activity in heart failure.