Transforming growth factor beta is one of the most abundant growth factors stored in bone. It is known as a potent regulator of osteoblast proliferation and differentiation as well as of production extracellular matrix. We established a highly specific RT-PCR in combination with HPLC for detection and quantification of TGFβ1 and TGFβ2 mRNA expression in 89 human bone samples. Levels of TGFβ1 protein ranged between 27 and 580 ng/g bone (mean 188±15 ng/g; n= 75) and for TGFβ2 between 7.2 and 35 ng/g bone (mean 14.3±2.1 ng/g; n= 57). TGFβ1 and TGFβ2 protein concentrations and TGFβ isoform mRNA expression in bone were not significantly different between the sexes. TGFβ isoform mRNA expression as well as protein content in bone declined age dependently. TGFβ1 and TGFβ2 protein and mRNA expression were different in bone samples from different sites of the skeleton indicating in part the regulation by mechanical stimuli. In contrast to TGFβ1, TGFβ2 mRNA expression was significantly enhanced in osteoarthritic bone compared to unaffected bone. These data are in concordance to previous results concerning the expression of TGFβ3 in bone. In conclusion, the data suggest distinct patterns' of expression of the TGFβ isoforms under physiological and pathological conditions in bone.