Abstract Background: Subclinical hypothyroidism (SCH) and gestational diabetes mellitus (GDM) are common endocrinological disorders related to pregnancy. Raised anti-thyroperoxidase antibody (Anti-TPO Ab) titer increases the risk of progression of subclinical hypothyroidism into overt hypothyroidism. Both conditions are known to affect maternal and fetal outcomes adversely. Aim and Objective: To determine the prevalence of subclinical hypothyroidism in pregnant women and it’s association with anti-thyroperoxidase antibody and gestational diabetes mellitus. Methods: This cross-sectional study was conducted in department of obstetrics and gynaecology in SMS medical college, Jaipur from November 2022 till March 2024. Pregnant women coming for their antenatal check-up and fulfilling the inclusion criteria were included, after taking informed and written consent. Thyroid profile (S. TSH, Free T4, Anti-TPO Ab) and 2hr, 75gm, oral glucose tolerance test were performed. The result obtained were analyzed in SPSS. Results: showed the prevalence of subclinical hypothyroidism was 40.56%, out of that 45.20% were anti-thyroperoxidase antibody positive. In our study the prevalence of GDM was 11.11%. Among SCH patients, 19.18% had glucose levels between 140-199 mg/dl compared to 5.6% euthyroid patients who had level between this range. Conversely, 80.82% SCH patients had levels below 140 mg/dl, while 94.39% euthyroid patients had glucose levels below 140mg/dl. The relative risk of developing GDM with SCH is 3.42 (95% CI: 1.38–8.49), with a p-value of 0.008 which was statistically significant. Conclusion: Our study showed high prevalence of subclinical hypothyroidism in pregnant women. A significant number of SCH cases were associated with elevated anti thyroperoxidase antibodies titres. Our study found a significant association between SCH and GDM.