A giant cervical goiter, defined as a thyroid mass larger than 8 cm in diameter, is usually a nodular or adenomatous goiter. A giant cervical goiter can also be caused by hyperthyroidism (i.e., Hashimoto's thyroiditis). The surgical indications for patients with Hashimoto's disease include suspected malignant tumors, persistent symptoms related to the disease, or persistent enlargement of the goiter. We herein describe a woman who developed symptoms of compression from a thyroid tumor, the volume of which was almost the largest reported in the relevant literature to date. The bilateral lobes of the giant thyroid tumor were removed by total en bloc excision. We protected the bilateral recurrent laryngeal nerve and preserved the bilateral upper and lower parathyroid glands in situ. The excised left lobe tumor was 16 × 9 × 5.5 cm, whereas the right lobe tumor was 12 × 8 × 4 cm. The pathological diagnosis was Hashimoto's thyroiditis. Although surgical excision is difficult, it is still the main treatment modality for giant goiters in patients with Hashimoto's thyroiditis and can help to reduce the occurrence of complications.