Primary non-Hodgkin's lymphoma (NHL) of the thyroid gland is a rare disease with an incidence of 0.5 per 100,000 population. Stages IE and IIE thyroid NHL have been traditionally treated by surgical resection; however, modern treatment consists of chemotherapy and local radiotherapy, and surgery is often reserved for tissue diagnosis and relief of airway compression. We retrospectively reviewed the management and outcomes of nine consecutive patients with thyroid NHL, eight females and one male (median age 63 yr, range 34-71 yr) treated between 1994 and 1999. Five patients had disease stage IE and 4 stage IIE. Median follow-up was 72 mo. Pathohistology and immunohistochemistry identified two patients with mucosa-associated lymphoid tissue (MALT), three follicular center cell lymphoma (FCC), two patients large B-cell lymphoma (BLCL), one a marginal zone lymphoma (MZL), and one patient a peripheral T-cell lymphoma (PTCL). Total thyroidectomy was performed in three patients and subtotal thyroidectomy in four. One (MALT) patient underwent surgery alone; three patients surgery, radiotherapy, and chemotherapy (two FCC, one PTCL); three patients surgery and chemotherapy (one MALT, one FCC, one LBCL); and two chemotherapy alone (one LBCL, one MZL). Median survival was 79 mo (range 13-124 mo). The PTCL patient, a 34-yr-old man, died from disseminated disease at 13 mo despite secondary chemotherapy, and one LBCL patient with extensively invasive local disease died from stroke 17 mo after diagnosis. The remaining seven patients remain in remission with no local or systemic relapse at a mean of 86 mo. With appropriate therapy primary thyroid NHL has a favorable course; however, prognosis depends on the histology, local spread, and the stage of the disease at presentation, as well as the patient's performance status. Surgery in combination with chemotherapy and/or radiotherapy is still warranted for intermediate and high-grade thyroid NHLs, with over 77% of patients achieving long-term remission. Peripheral T-cell lymphoma carries a poor prognosis.