Summary: Recordings of early and late auditory evoked potentials and spectral analysis of scalp EEGs of 14 eight- and nine-year-old boys with difficulties in reading, writing and spelling were compared with those of 18 matched controls. The recordings of the poor readers lacked the normal asymmetry of central conduction time and wave amplitude in the early (brainstem) auditory evoked potentials, and late (cortical) evoked potential components were reduced in amplitude. Spontaneous EEG activity was significantly increased in power in all spectral bands, and this activity was less responsive to changes in sensory stimulation. These observations provide evidence for disturbed early and late auditory processing and altered cortical function. Correlations with behavioural measures considered to be indices of reading, writing and spelling ability support the view that the electrophysiological differences in the group of poor readers reflect a disturbance in the mechanisms subserving the acquisition of written language. These differences are consistent with a primary disturbance of selective attention, which may contribute to a less efficient cognitive strategy for the acquisition of reading skills.