Calcitonin, a natural polypeptide hormone, has been used in the treatment of osteoporosis for almost 30 years. Despite the fact that its efficacy, safety and analgesic effect have been already confirmed, calcitonin is now a second choice antiresorptive drug. It is considered that the main reason of limited calcitonin use is the lack of oral calcitonin formulation in the market. Many approaches have been already tested to achieve calcitonin bioavailability and efficacy after oral administration such as encapsulation of calcitonin into polymeric carriers (nano- and microparticles), liposomes, pegylation technology, use of protease inhibitors or absorption enhancers. Currently, most advanced studies on calcitonin-containing oral tablets are in the phase III clinical trials.