Osteoporosis is a systemic skeletal disease characterized by low bone mineral density (BMD) and micro-architectural deterioration of the bone tissues resulting in bone fragility and susceptibility to fracture. It is caused by the decrease of bone formation and the increase of bone resorption. Both bone formation and resorption can be examined by the circulating biomolecules. The biomolecules using in determining the bone formation are composed of osteocalcin (OC) in form of N-terminal midmolecule fragment (N-MID) and undercarboxylated osteocalcin (UcOC). The other bone formation markers are matrix Gla protein (MGP) and N-terminal propeptide of Type I collagen (PINP) whereas the biomolecules using in determining the bone resorption comprises of C-terminal cross-linking telopeptide of Type I collagen (betaCTx), collagen cross-links molecules which are pyridinoline (PYD) and deoxypyridinoline (DPD). Nevertheless, some vitamins such as vitamin D (Vit D) and some hormones e.g. parathyroid hormone (PTH) are also affected to the bone quality. To monitor and assess the bone mass, the normal values of bone markers as well as the relevant biomolecules are important and should be established. The researchers aimed to investigate the normal values of the interesting bone biomarkers and the relevant biomolecules in the adult volunteers.