Objective: Alzheimer's disease is characterized by progressive, irreversible brain damage and cognitive decline. Although the diagnosis and treatment of the prodromal symptoms of dementia are important, no treatment for mild cognitive impairment has been currently established. Herein, we report the case of an 80-year-old female patient with memory complaints treated with <i>Gugijihwang-tang</i>, a traditional Korean medicine herbal formula, as an add-on medication.Case Presentation: The patient was diagnosed with mild cognitive impairment based on clinical examinations using the Mini-Mental State Examination (MMSE), the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Activities of Daily Living (ADL) Scale, Global Deterioration (GDR) Scale, and Clinical Dementia Rating (CDR) Scale. She was treated with <i>Gugijihwang-tang</i> bis in die for 12 months while continuing her original medications, including 5-mg donepezil and 590-mg acetyl-l-carnitine. The MMSE score in the Korean Version of the CERAD Assessment Packet increased from 21 to 27 during the 12-month treatment period, and the CERAD 2 score increased from 33 to 62. The instrumental ADL scale score improved from 11 to 5. Other clinical examination results also showed improvement. The patient was satisfied and experienced no significant adverse events related to the <i>Gugijihwang-tang</i> treatment.Conclusion: This case suggests that <i>Gugijihwang-tang</i> could be considered as a treatment method for patients with mild cognitive impairment.