Background and objectives: Subclinical hypothyroidism is an asymptomatic condition with normal thyroxin and raised thyroid stimulating hormone (TSH) level. It affects 3- 15% of adult population. Large scale population based studies on the prevalence of subclinical hypothyroidism in India are scarce. So this study was done to estimate the prevalence of subclinical hypothyroidism in patients attending OPD in ANMMCH, GAYA and find out the relationship of TSH level with age, sex, family history, body mass index, and other co-morbid conditions