Ankylosing spondylitis, characterised with excessive new bone formation and calcification in spine and peripheral joints, causes osteoporosis which is a general component of inflammatory arthritis. Since is excessive bone formation  affects bone mineral density, there are problems in diagnosis and follow-up of osteoporosis efforts made for finding the right diagnostic tool. Besides bone metabolism and turn-over in inflammatory diseases should be known in detail, because it has a place in diagnosis and follow-up. In this review, bone mineral density in ankylosing spondylitis, the importance and usage of bone turn-over parameters are discussed in the light of literature data.
Key words: Ankylosing spondylitis, osteoporosis, bone mineral density, bone formation and resorbtion markers