Cholera toxin B subunit conjugated to saporin (SAP, a ribosomal inactivating protein that binds to and inactivates ribosomes) was injected into both stellate ganglia to evaluate the physiological response to targeted ablation of cardiac sympathetic neurons. Resting cardiac sympathetic activity (cardiac sympathetic tonus), exercise-induced sympathetic activity (heart rate responses to graded exercise) and reflex sympathetic activity (heart rate responses to graded doses of sodium nitroprusside, SNP) were determined in eighteen adult conscious Sprague-Dawley male rats. Rats were randomly divided into 3 groups (n = 6/group): 1) Control (no injection), 2) Bilateral stellate ganglia injection of unconjugated cholera toxin B (CTB) and 3) Bilateral stellate ganglia injection of cholera toxin B conjugated to SAP (CTB-SAP). CTB-SAP rats, compared to control and CTB rats, had reduced cardiac sympathetic tonus as well as reduced heart rate responses to graded exercise and graded doses of SNP. Furthermore, the number of stained neurons in the stellate ganglia and spinal cord (segments T1-T4), was reduced in CTB-SAP rats. Thus, CTB-SAP retrogradely transported from the stellate ganglia is effective at ablating cardiac sympathetic neurons and reducing resting, exercise and reflex sympathetic activity. Additional studies are required to further characterize the physiological responses to this procedure as well as determine if this new approach is safe and efficacious for the treatment of conditions associated with excess sympathetic activity (e.g. autonomic dysreflexia, hypertension, heart failure and ventricular arrhythmias).