Background: Amiodarone (AMD) is a highly effective antiarrhythmic agent. Its utilization is associated with toxic effects on thyroid gland. The aim of this research to evaluate the AMD chronic administration potential toxic impact on the thyroid gland and evaluate Alfa lipoic acid (α LA) possible protective impact. Materials and methods: 40 adult male albino rats were equally separated into 4 groups, group I (control) given 1ml distilled water for 12 wks., group II (AMD tested group) received a single dose of 40 mg/kg /day AMD for 12 wks. Group III (AMD+ α-LA), where AMD was given as group II and a dose of 100 mg/kg of α-LA for 12 weeks, group IV received AMD in doses similar to group II, then the drug was withdrawn and the rats took no treatment for additional 4 weeks. All groups were sacrificed after 12 weeks except group IV after 16 weeks from the beginning of the experiment. Results: In AMD treated group; the T3, T4 and catalase [CAT] serum levels were significantly reduced along with significant elevation in TSH, IL6 and malondialdehyde [MDA] level, light microscopic examination of AMD group showed cellular degeneration of follicles and colloid peripheral vacuolation along with strong positive immune reaction for Ki-67 declared in AMD group as compared to those of other groups. Additionally, electron microscopic studies supported these results. Conclusion: Chronic administration of AMD induced thyroid damage which could be improved by Co-supplementation of α-LA.