Osteoporosis is a systemic skeletal disease characterized by loss of bone mass and microarchitectural deterioration of the bone tissue. This results in increased bone brittleness. The World Health Organisation (WHO) classified osteoporosis as one of the ten most widespread diseases in the world. In Austria only, is estimated that 740,000 people suffer from osteoporosis. The loss of the bone mass is mostly caused by changes in serum levels of the sex hormones, which are particularly pronounced in women during and after the menopause. Therefore, the postmenopausal women are most likely to be affected by osteoporosis. This thesis explains the detailed relationship between the sex hormones and decrease in bone mass with the emphasis on the drug therapy from the perspective of currentresearch.