Wernicke Encephalopathy (WE) is a severe neurological disease caused by vitamin B1 (thiamine) deficiency, which is potentially treatable if early diagnosed. This is the clinical case of a young female patient, with renal insufficiency on haemodialysis, who has been submitted to an abdominal surgery. After the intervention, there were difficulties on beginning with enteric nutrition. Some days later she developed gait imbalance. A Brain Magnetic Resonance (MR) was performed and disclosed abnormalities suggestive of WE. After treatment with thiamine, the patient became asymptomatic. Brain MR is crucial for the confirmation of the diagnosis and early detection of WE, as the imagiologic pattern is typical and the clinical diagnosis is frequently difficult to obtain.