We have utilized immunocryoultramicrotomy to detect synapsin, somatostatin, parvalbumin, and tubulin at the ultrastructural level. Immunocryoultramicrotomy combines informative identification of morphology with accurate immunolabeling. Moreover, since no detergents or organic solvents are used to enable antibody penetration, and since no enzyme marker diffusion occurs, localization of the antigens should be more accurate. Accordingly, it was possible to localize precisely all four antigens within a well-preserved structure. Application of this method has important advantages for high-resolution localization of molecules relevant to neuronal function.