Rapid restoration of nutrients and electrolytes after prolonged starvation could result in a life threatening condition characterized by sensory and neurological dysfunction and severe metabolic imbalance that has been designated as refeeding syndrome. Its diagnosis is frequently missed resulting in severe complications and even death. We describe a 25-years-old female patient with mental disorders and severe malnutrition who developed severe clinical manifestations and biochemical abnormalities characteristic of the refeeding syndrome, after restarting oral feeding on her own. Schizophrenia was later diagnosed. Increased awareness of this condition and its complications is necessary to prevent its detrimental complications.