Here we report a rare case of primary T-cell lymphoma of the thyroid gland. A 32-year-old Chinese man was admitted to our hospital because of marked goiter and subcutaneous nodules. Computed tomography (CT) scan of the neck disclosed diffuse enlargement of the thyroid gland. A diagnosis of peripheral T-cell lymphoma was made according to cytopathological findings of fine-needle aspiration (FNA) of the thyroid gland and skin biopsy. Immunohistochemistry stain showed that the tumor was positive for CD3 and negative for CD20. Clonal T-cell receptor (TCR-γ) gene rearrangements were demonstrated by polymerase chain reaction. After six cycles of combination chemotherapy (bleomycin, cyclophosphamide, doxorubicin, vincristine, and prednisone), the thyroid retracted to normal size gradually.