Thyroid adenoma is a common disease. If partial thyroidectomy is performed, postoperative suppression therapy is often given to avoid nodule development in the remaining thyroid. It is unclear whether this treatment is warranted. Patients who underwent a partial thyroidectomy with a histologic diagnosis of follicular thyroid adenoma from January 1985 until February 1998 were studied retrospectively. Patients were analyzed on the basis of postoperative therapy, new thyroid nodule growth, and costs. Seventy-six patients were identified with a recurrence rate of 4 per cent (3/76). Sixty-one per cent (46/76) were treated with postoperative thyroid suppression therapy, and no difference in new nodule development was noted with at least 6 months of follow-up (P = 0.274). No patients required reoperation. A large cost saving was shown for patients who were not treated with levothyroxine. We conclude that postoperative thyroid suppression may not be routinely indicated. A prospective, randomized study would be necessary to answer this question conclusively.