Active vitamin D is a second line treatment followed by bisphosphonate in the Japanese guideline of glucocorticoid-induced osteoporosis (GIO) . Although it shows relatively mild but significant effect on BMD and fracture prevention, it is utilized as combination therapy with bisphosphonate. Vitamin D is recommended for GIO with gastrointestinal disease and hepatobiliary disorders. Vitamin D may be the first line treatment for younger GIO patients.