Forty-five elderly female osteoporotics were given daily dose of 750 mg of calcium and 1.0 microgram of activated vitamin D (1-a hydroxyvitamin D) orally for 24 months to evaluated the effect of drugs on bone mineral density. Bone mineral density was evaluated and repeated every 6 months for 2 years. Average bone mineral density (L (2)-L (4)) and T score were 0.773 (SD 0.120) and -2.90 (SD 0.97) before treatment, and increased to 0.808 (SD 0.121) and -2.59 (SD 0.97) after 24 months of therapy, respectively (p<0.01). During treatment, complications including hypercalcemia, hypercalciuria, or renal stone were not observed, and indicators of renal function were normal. Therefore the activated vitamin D treatment in osteoporosis is effective in diminishing normal decline of bone mineral density, especially in areas with low calcium and vitamin D intake, such as South Korea.