Embryonic tissue (E14-E16) of the olfactory bulb and substantia nigra resp. was transplanted to neonatal rats into cavities formed by partial or total unilateral bulbectomy. After 40 days of survival the animals were perfused with Bouin's fluid and processed for histological examination. Complete series of 10 microns horizontal or sagittal sections were stained with Gill haematoxylin and Bodian's silver method. To demonstrate the olfactory protein immunohistochemical staining with peroxidase-antiperoxidase was used. After bulbectomy degeneration of the axons of the olfactory cells occur, which subsequently regenerate, penetrate into the transplant and form typical glomerular structures in the latter. By immunohistochemical staining in both types of transplants olfactory structures were reliably differentiated from non-olfactory elements.