A middle aged male presented with acute bilateral vision loss, 4 weeks after undergoing gastric bypass surgery for gastric carcinoma. He had normal sensorium, fundoscopy, normal pupillary reaction to light, but had mild opthalmoparesis and nystagmus with ataxia. Magnetic resonance imaging of the brain revealed post-chiasmatic optic tract edema along with other classical features of Wernicke's syndrome. Thiamine supplementation leads to complete resolution of clinical as well as imaging findings. In appropriate clinical settings, a high index of suspicion and early treatment are essential for managing Wernicke's syndrome even in patients with atypical clinical and imaging presentation.