A 48-year-old woman with a 9-year-history of anorexia nervosa (AN) was admitted complaining of generalized bone pain. Blood tests showed hypocalcemia and hyperphosphatasemia, and a radiological survey revealed multiple rib fractures, suggesting complication with osteomalacia. Two years earlier, she had undergone subtotal colectomy for colon cancer. Her serum 25-hydroxy vitamin D concentration was below the detectable level. In addition to a poor nutritional intake and insufficient sun exposure, malabsorption of fat-soluble substances in the intestine and phosphate loss from the kidneys might have contributed to the development of her osteomalacia.