Introduction: Osteoporosis is the most common skeletal disorder and is considered a risk of fracture. Most medication used for the treatment of osteoporosis are antiresorptive; however strontium therapy in postmenopausal women has shown a double effect on resorption and bone formation. Objective: To evaluate the effect of strontium on bone mineral density (BMD) and circulating biochemical markers of bone turnover in postmenopausal women who had a decreased BMD. Material and methods: A prospective study was carried out in 23 postmenopausal women who had decreased BMD, who received daily strontium orally by night during 12 months. Evaluation of BMD at lumbar spine and hip as well as biochemical markers in blood for bone turnover before and during therapy. Results: BMD at the spine (0.755 + 0.104 to 0.792 + 0.094, p < 0.05) and hip (0.833 + 0.096 to 0.856 + 0.100, p < 0.05) increased significantly after 12 months of treatment. Bone turnover markers showed a decrement of osteocalcin, by contrast the specific alkaline phosphatase increased after 6 months of therapy; however C-terminal telopeptide of type 1 collagen was not modified. Conclusions: Strontium ranelate increased significantly BMD at the spine and at the hip in postmenopausal women and simultaneously improved bone turnover estimated by circulating bone markers. Key words: strontium ranelate, osteoporosis, bone mineral density, menopause.