Transgenic mice were generated in which the regulatory sequences for the Col2a1 gene were used to drive expression of Cre recombinase in chondrocytes. The strain initiates Cre-mediated recombination predominantly in immature chondrocytes and the inner layer of perichondrial cells within the developing endochondral skeleton . However, there is also significant Cre-activity in other regions of the embryo reflecting the widespread expression of Col2a1.