Bone mass is the lifelong result of a balance between bone formation and bone resorption as shown in most metabolic bone diseases including involutional osteoporosis. To date, bone turnover has been precisely assessed by bone histomorphometry made by bone biopsy and also calcium kinetics and balance studies. However, bone histomorphometry is an invasive procedure requiring specialized laboratory for processing and evaluation, and calcium kinetics and balance studies require administration of radioisotopes and long periods of observation. Therefore, these procedures are not suitable for clinical tests of evaluation of bone turnover. Recently several biochemical parameters for bone turnover have been developed and also a number of noninvasive procedures such as single and dual photon absorptiometry, dual energy x-ray absorptiometry, computed tomography and ultrasound velocity, have been developed to quantitate bone mass more sensitively. In this symposium "Bone turnover and clinical tests" five symposists talked and discussed about some biochemical parameters for bone turnover and noninvasive procedures for measurement of bone mass.