Children with callosal agenesis have congenital absence of the corpus callosum. Previous analyses of these subjects have shown that they have significant difficulty on rhyming tasks and tasks of explicit sound organisation. This study investigated whether such difficulties were also manifested on simpler tasks requiring the discrimination and repetition of similar sounding linguistic material. None of the acallosal children tested performed at a normal level across tasks. This suggests a possible impairment in the initial registration or analysis of auditory material and possible bases for this deficit are discussed. In cases of callosal agenesis in which impairments in auditory discrimination are more severe there may be a more profound impact upon language development.