Expansion of articular chondrocytes in monolayer culture leads to loss of the unique chondrocyte phenotype and the cells' redifferentiation capacity. Dedifferentiation of chondrocytes in monolayer culture is a challenging problem for autologous chondrocyte transplantation (ACT). It is well established that Igf-I exerts positive anabolic effects on chondrocytes in vivo and in vitro. Accordingly, in this study, we examined whether the anabolic insulin-like growth factor-I (Igf-I) is capable of extending the chondrogenic potential of dedifferentiated chondrocytes in vitro.