Osteoblast Mineralization Medium (ObMM), when used with Osteoblast Mineralization Supplements (ObMS-A, Cat #4672-A and ObMS-B, Cat #4672-B), and 25 ml of fetal bovine serum (FBS) is a complete medium designed for the maturation of normal osteoblasts in vitro. It is a sterile, liquid medium which contains essential and non-essential amino acids, vitamins, organic and inorganic compounds, hormones, growth factors, trace minerals and a low concentration of fetal bovine serum (5%). The medium is HEPES and bicarbonate buffered and has a pH of 7.4 when equilibrated in an incubator with an atmosphere of 5% CO₂/95% air. The medium is formulated (quantitatively and qualitatively) to provide an optimally balanced nutritional environment that selectively promotes maturation and mineralization of normal osteoblasts in vitro.