Immunocytochemical staining of the dorsal nucleus of the lateral lemniscus with a well characterized antiserum to glutamate decarboxylase reveals that all, or nearly all, cells in this nucleus show immunoreactivity without the use of agents to block axonal transport. Most somata and dendrites are also contacted by immunoreactive axonal endings. It has previously been established that this nucleus is richly innervated by ascending lemniscal fibers and contains different types of neurons that project to the inferior colliculus. One may conclude that this precollicular nucleus is a major GABAergic feedforward inhibitory center in the acoustic pathway.