In order to investigate the role of protein kinase C (PKC) in chondrogenic differentiation, we examined the localization of PKC isoforms in a limb bud micromass culture system. PKC$alpha$ is specifically localized in the regions which would become cartilage nodules, while PKC$lambda/l$ and $zeta$ display widespread distribution in the whole culture. Distribution of PKC$alpha$ change along with promotion or inhibition of chondrogenesis by lysophosphatidylcholine or phorbol 12-myristate 13-acetate. On the other hand, localization of PKC$lambda/l$ or $zeta$ a was not changed by the modulation of chondrogenesis. Peanut agglutinin binding protein which is associated with cell aggregation during chondrogenesis was present in the cell condensation regions and its expression in those regions was influenced by PKC activity. Expression of fibronectin and N-cadherin in the cell condensing area were also affected by modulation of PKC activity. These results suggest involvement of PKC$alpha$ in the cell condensation, possibly through regulating expression of fibronectin and N-cadherin.