ABSTRACT: Thyroid disorders are common in women. Obstetrician–gynecologists are at the forefront of the diagnosis of all forms of thyroid disease, including hypothyroidism, hyperthyroidism, thyroid nodules, multinodular goiters, and thyroid cancer. These conditions must be evaluated in a timely and cost-effective manner. Treatment of mild hypothyroidism often can be initiated by the obstetrician– gynecologist, whereas further diagnostic testing and therapy for hyperthyroidism and thyroid nodules may require the assistance of internists, endocrinologists, and surgeons. The correct management of hyperthyroidism and hypothyroidism in pregnancy will ensure optimal maternal and fetal outcomes. After delivery, it is important to recognize postpartum thyroiditis and its possible relationship to postpartum depression. Population screening for mild thyroid disease is recommended by some professional societies, especially in women who are older than 60 years or have a positive family history of thyroid disease or other autoimmune diseases or in young women who may wish to become pregnant.