The incidence of goiters in children is about 4% to 5%. The first step in the evaluation is to decide whether the swelling indeed involves the thyroid. After careful examination, one determines if the thyroid is diffusely or focally enlarged. A solitary nodule merits an extensive workup because of the high rate of malignancy. The evaluation of a diffuse goiter proceeds after deciding if the patient is euthyroid, hypothyroid, or hyperthyroid. In most cases, the child is euthyroid and the diagnosis is either CLT or simple colloid goiter. Laboratory tests for thyroid function and antibodies usually make the diagnosis. The hypothyroid patient most likely has CLT, although drugs or goitrogens, dyshormonogenesis, and thyroid resistance are also possible. The hyperthyroid patient usually has Graves' disease. The incidence of malignancy of solitary thyroid nodules is 15% to 40%; therefore, evaluation must be sensitive enough not to miss cancer. Ultrasonography helps to delineate the anatomy and to reveal if the nodule is cystic. Radionuclide scans are useful, as warm or hot lesions are rarely malignant. Cold nodules require further investigation, and in most institutions, this amounts to open biopsy. Fine-needle aspiration may be used if the clinician and pathologist are experienced. With this aggressive approach to thyroid nodules, malignancies are given early treatment. The prognosis is good in most thyroid carcinomas.