Thyroid gland dysfunctions are among the most prevalent endocrine disorders in India. Although serum ferritin levels are known to be altered in hypothyroidism, limited data exist on ferritin status in autoimmune hypothyroidism. This study aimed to evaluate serum ferritin levels in patients with anti-TPO-positive autoimmune hypothyroidism. A comparative cross-sectional study was conducted at tertiary care hospital, Ayodhya, involving 80 newly diagnosed autoimmune hypothyroid patients (aged 25–55 years) and compared with 80 healthy controls. Biochemical parameters including fasting plasma glucose (FPG), thyroid profile, and serum ferritin were analysed. Data were statistically evaluated using SPSS version 29.0. The mean serum ferritin level was significantly lower in the hypothyroid group (17.15 ± 9.44 ng/mL) compared to controls (73.13 ± 44.46 ng/mL), with a p-value <0.0001. A strong negative correlation was found between TSH and serum ferritin levels (r = –0.68). These findings indicate a significant association between autoimmune hypothyroidism and reduced serum ferritin levels. This is the first study in the Ayodhya region of Eastern Uttar Pradesh to highlight this correlation, offering valuable insight into the relationship between thyroid function and iron metabolism.