The refeeding syndrome can develop when seriously undernourished or starving persons resume to a 'normal' eating schedule. The syndrome is caused mainly by severe hypophosphatemia and other metabolic complications. This can interfere with the functioning of a number of organs and can have life-threatening consequences and even cause death. The article reports on two patients with anorexia nervosa who developed the refeeding syndrome while receiving clinical treatment. The pathogenesis, possible complications and treatment for the syndrome are described and attention is given to possible preventive measures. The purpose of the article is to further the recognition and prevention of the refeeding syndrome in psychiatric patients.