The taste buds and their nerves in the guinea pig were immunocytochemically investigated with regard to the localization of spot 35 protein, neuron-specific enolase (NSE), neurofilament protein (NFP), and S-100 protein. The spot 35 protein-like immunoreactivity was confined to slender cells comprising half the number of taste bud cells. NSE-like immunoreactivity was recognized in some taste bud cells as well as nerve fibers both within the taste bud and in the subepithelial connective tissue. The NSE-immunoreactive cells were divided into two cell populations: one weakly and the other intensely immunoreactive. The former cells proved to be spot 35 protein-immunoreactive. Moreover, the cells immunoreactive for both spot 35 protein and NSE were frequently associated with nerve fibers immunostained intensely for NSE. The NFP- and S-100 protein-like immunoreactivities were found in none of cells in the taste bud, but exclusively in the subepithelial neural elements.