Graves' disease and Hashimoto's thyroiditis are the most common autoimmune thyroid diseases. Hypothyroidism can develop in patients with Graves' disease, either spontaneously or as a result of radioactive iodine therapy or surgery. However, it is rare for patients with Hashimoto's thyroiditis to subsequently develop Graves' disease. We report a case of alopecia areata associated with Graves' disease in a 41-year-old woman who had previously been diagnosed with Hashimoto's disease. Alopecia areata is an autoimmune disease associated with other autoimmune diseases such as thyroid disorders, anemia, and other skin disorders.