Primary hyperparathyroidism (PHPT) is a common disorder often associated with reduced bone mineral density (BMD) and osteoporosis. The main goal in treating patients who refuse surgery is the correction of bone complications. The aim of this study is to evaluate safety and efficacy of alendronate treatment in patients with PHPT and osteoporosis. Eligible patients were postmenopausal women suffering from PHPT who did not meet surgical guidelines or ignored surgery due to different reasons. 55 osteoporotic or osteopenic women received alendronate 70 mg weekly and 43 were leaved under medical observation for the reasons of not being osteoporotic or financial unable to comply with treatment/ Results: After 2 years of treatment alendronate group showed statistically significant gain in BMD at L24 +4,0±4,2%, Neck +2,2±4,4%„ TH +2,3±4,5%. At the same time observational group showed decrease in BMD at L24 -4,2±4,0%, TH -3,5±3,8%, R33% -4,0±6,5%, [95% CI -7,6; -0,4]. On the whole BMD dynamics in groups differed at the following sites: L2 (p=0,00004), Neck (p=0,005), TH (p=0,001), R33% (p=0,006). ' Alendronate intake was accompanied by serum Ca decrease (at 1 year point -4,3±5,4%, p=0,00005, at 2 year -2,7±6,4%, p=0,04), 24 hours'Ca excretion decrease from (Me) 8,5 to 6,3 mmol/day at 1 year point, (p=0,007) without PTH elevation. As well as CTx fell at Me: 66% at 1 year and at 60% at 2 year point and OK at 39% and at 27%, correspondingly, p