The Hoxc8 expression pattern was examined in mouse embryos 7.5-12.5 days postcoitum (dpc) using whole-mount in situ hybridization and RT-PCR. The expression of Hoxc8 started between 7.5 and 8.5 dpc. A strong expression was detected in the ectoderm and mesoderm at 8.5 dpc. At 9.5 dpc, a distinct anterior boundary of Hoxc8 expression was established at the 10th and 16th somites in the neural tube and the paraxial mesoderm, respectively. This staggered expression pattern was maintained throughout the later stages. By 12.5 dpc, the forward progression of the Hoxc8 expression pattern was observed and the stain was weakened. In the ectoderm-derived neural tube, strong Hoxc8 expression was observed in the ventral horn and later in the ventral and mediolateral region of the mantle layer, indicating a possible association with the onset and progression of neural differentiation. In the case of the mesoderm-derivative cells, strong Hoxc8 expression was detected in the sclerotome on the way to the notochord and neural tube and mesonephros, suggesting a role of Hoxc8 in the formation of the vertebrae and ribs and the possible involvement in the differentiation into the kidney.