Background: Thyroid disorders are among the common endocrine problems in pregnant women. Often overlooked in pregnancy due to nonspecific symptoms and hyper-metabolic state of pregnancy. Western literature shows prevalence of hypothyroidism in pregnancy as 2.5% and hypothyroidism as 0.1-0.4%. There is paucity of data on prevalence of thyroid disorders in India pregnant population. This study was carried out to know prevalence of thyroid disorders in pregnant women in Indian population.Methods: One hundred pregnant women attending antenatal clinic in first trimester were registered. Detailed history and examination was done. Apart from routine basic and obstetrical investigations, TSH, FT3 and FT4 level estimation was done.Results: Prevalence of thyroid dysfunction was high in this study in first trimester pregnant women, with subclinical hypothyroidism in 6%, overt hypothyroidism in 2%, subclinical hyperthyroidism 2 % and overt hyperthyroidism 0%.Conclusions: Prevalence of thyroid disorders, especially subclinical hypothyroidism (6%), overt hypothyroidism (2%) and subclinical hyperthyroidism (2%) was high. To prevent adverse effects on maternal and fetal outcome, we are emphasizing the importance of routine antenatal thyroid screening.