The distribution and morphology of glycinergic synapses in the cochlear nucleus were investigated using monoclonal antibodies against the glycine receptor. Glycine receptor immunoreactivity was seen on somas and proximal processes of most cells in all divisions of the cochlear nucleus; distribution of label in neuropil was denser in the dorsal cochlear nucleus and granule cell cap than in the ventral cochlear nucleus. At the ultrastructural level, glycine receptor immunoreactivity was specifically distributed postsynaptically to terminals that contained flattened vesicles in the guinea pig anteroventral cochlear nucleus. These studies show that the immunocytochemical localization of the glycine receptor can provide a means of identifying and characterizing glycinergic synapses throughout the central nervous system.