The distribution of the alpha 7 nicotinic receptor subunit in the rat cerebellum was studied immunohistochemically at the electron microscope level using an alpha 7 subunit-specific antibody. The granule cell layer showed a much lower level of immunoreactivity for the alpha 7 subunit than the Purkinje cell layer. Granule cell somata were completely devoid of labeling; this appeared to be restricted to glomeruli exclusively located in the membranes of granule cell dendrites. The alpha 7 immunolabeling was located not at active synaptic areas but was mostly perisynaptic. This localization suggests that nicotinic receptors containing the alpha 7 subunit could have a modulatory function and/or play a direct role in the generation of synaptic currents.