Wernicke's encephalopathy (WE) is an acute or subacute neuropsychiatric condition associated with thiamine deficiency that is more often seen in cases of alcohol abuse. The current study presents a rare case of primary cervical cancer complicated by WE. A 44-year-old woman who underwent a laparoscopic radical hysterectomy with endoscopic pelvic lymphadenectomy for primary cervical adenocarcinoma in 2014 developed multiple metastases in the pelvic and abdominal cavities, right iliopsoas muscle and iliac wing 2 years post-surgery. The patient was hospitalized due to the rupture of a mass in the right lower abdomen in August 2019. A computed tomography scan demonstrated the spreading of primary cervical cancer to the right lower abdomen, which broke through the skin. In this terminal stage of cervical cancer accompanied with malnutrition, the patient suddenly presented with cognitive impairment, particularly in recent and immediate memory, as well as bilateral sustained nystagmus during hospitalization. Brain magnetic resonance imaging showed hyperintensity in the periaqueductal midbrain on T2 fluid-attenuated inversion recovery imaging. Based on these findings, a diagnosis of WE was made, and thiamine (100 mg) was immediately administered intramuscularly three times a day. After a week, the patient's eye movement disorder and recent memory improved gradually. The present case report with literature review aims to demonstrate the significant comorbidity between cancer and WE, raising awareness about the importance of recognizing the risk of thiamine deficiency in advanced cancer to prevent the development of WE.