Background: Diabetes carries a two-fold risk of Sudden Cardiac Death (SCD). Diabetic Autonomic Neuropathy (DAN), often progressing to Cardiovascular Autonomic Neuropathy (CAN, critically low parasympathetic tone [P]), increases death 3.5-fold over 5 years, half sudden or non- renal. Oxidative stress is a major cause of DAN. Also, increased sympathetic tone (S), High Sympathovagal Balance [SB>2.5] increases SCD risk. Objective: Dysautonomic diabetic II patients were treated with the antioxidant (r) Alpha Lipoic Acid (ALA), autonomic function followed, and Sudden Death (SD) compared to untreated patients. Methods: 133 patients (mean age 66y/o) with DAN or CAN, diagnosed using the ANX 3.0 Autonomic Monitor (Physio PS, Inc., Atlanta, GA) was offered (r)-ALA: 83 agreed (Group 1), and 50 refused (Group 2). P and S were re- measured up to 3 times/yr (mean f/u 6.31 yrs); SCDs were recorded. Results: A 43% Relative Risk Reduction (RRR) in SCD occurred with (r)- ALA (25% SCD Group 1 vs. 44% SCD Group 2, p=0.0076). Initial to final patients with high SB or CAN were 21.7%-12% (p=0.010), 10.8%- 15.7% (p=0.045), Group 1 vs. 24%-22% (p=ns), 6%-12% (p=0.083), Group 2. Only Group 1 survivors increased mean resting P. The progressive increase in P’s decline, increasing CAN risk, in the other patients correlated with mortality (p<0.001) and (r) ALA dose. Initially, Group 1 had insignificantly less high SB (p=0.449) and significantly more CAN (p=0.013) vs. Group 2. Finally, Group 1 had significantly less high SB (p=0.0967) vs. Group 2, also improving to insignificantly more CAN (p=0.261). Conclusion: (r)-ALA was associated with a 43% RRR of SCD and favorable P and S changes.