In marsupial teeth, long cellular processes from ameloblasts and odontoblasts are found in the developing enamel and dentinal tubules, respectively. It has been suggested that the odontoblast cytoskeleton plays a role in the dentinal tubule formation of rat. To understand the role of the cytoskeleton in the blast cells, the location of vimentin and cytokeratin in the tooth germ of the bandicoot and the possum was examined using immunohistochemical techniques. Vimentin was detected in differentiating and secretory ameloblasts and may be involved with the secretion of fibronectin. Vimentin labelling was much weaker and irregular in cells of the outer enamel epithelium, the stellate reticulum and the stratum intermedium. Dentinal tubules, odontoblasts and dental papilla fibroblasts also stained positively for vimentin. Positive staining for cytokeratin was observed in all cells in the enamel organ but not in the enamel and dentinal tubules or the cells of the dental papillae. The presence of vimentin in the dentinal tubules indicated that the odontoblast processes in these tubules were still active and they extended to near the enamel-dentin junction. In conclusion, the presence of vimentin in tooth germ cells suggests that it may be involved in the formation of enamel tubules in marsupials.