Many kinds of information are carried in the acoustic signal that reaches auditory receptor cells in the cochlea. The analysis of this information is possible in large part because of the neuronal architecture of the auditory system. The mechanisms that establish the precise circuitry that underlies auditory processing have not yet been identified. The Eph receptor tyrosine kinases and their ligands are proteins that regulate axon guidance and have been shown to contribute to the establishment of topographic projections in several areas of the nervous system. Several studies have begun to investigate whether these proteins are involved in the formation of auditory system connections. Studies of gene expression show that Eph proteins are extensively expressed in structures of the inner ear as well as in neurons in the peripheral and central components of the auditory system. Functional studies have demonstrated that Eph signaling influences the assembly of auditory pathways. These studies suggest that Eph protein signaling has a significant role in the formation of auditory circuitry.