A previously healthy 3-year-old boy was referred because of persistent fever and anterior neck swelling and pain. The diagnosis of a mixed bacterial abscess of the thyroid gland was made. Incision and drainage were performed, and fever abated immediately. Antibiotic therapy was given in the hospital and for ten days after discharge. Acute suppurative thyroiditis is a rarely encountered infection. The majority of cases reported in the recent literature are from Japan. The case presented here, from the United States, demonstrates the difficulty that can be encountered in diagnosing this type of thyroiditis.