Refeeding syndrome is a life-threatening but treatable condition occurring in any patients with starvation. Electrolyte imbalance, especially hypophosphatemia and fluid shift result in metabolic changes in various systems. The authors reported a case of refeeding syndrome associated with prolonged starvation due to delusion and hallucination in a 38-year-old schizophrenia patient. Hypophosphatemia, hypokalemia, edema and elevation of liver enzyme was occurred despite careful treatment. The symptoms were improved after consistent electrolyte supplement. Close observation and repetitive monitoring are important to prevent refeeding syndrome.