The most effective treatment for pathological obesity is bariatric surgery; however, a patient may postoperatively develop vitamin deficiencies. In inadequate intake of food and its malabsorption after surgery, there are chiefly deficiencies of vitamins B1, B6, B12, and vitamin E, leading to complications as central and peripheral nervous system dysfunctions. The most marked nervous system changes are observed as polyneuropathy and severe Wernicke’s encephalopathy in vitamin B1 deficiency. Vitamin B12 deficiency clinically manifests as funicular myelosis and polyneuropathy. Polyneuropathy results from the inadequate intake of vitamin B6 and vitamin E. The larger number of bariatric surgical patients generates a need for alertness to the development of neurological complications in this cohort of patients as only early treatment initiation guarantees a favorable outcome of neurologic deficit.