We compared the effects of focussed attention upon event-related brain potentials (ERPs) to peripherally and centrally located visual stimuli in congenitally deaf subjects (Ss). The results were compared with those obtained from a group of normal hearing Ss in the same paradigm. ERPs from deaf and hearing Ss displayed similar attention-related changes with attention to the centrally located stimuli. These included enhanced amplitudes of the N1 component (157 ms) over the occipital regions of both hemispheres. By contrast, with attention to peripheral visual stimuli, ERPs from deaf Ss displayed attention-related increases that were several times larger than those from hearing Ss and different in scalp distribution. Whereas for hearing Ss the principal effects of attention to peripheral stimuli occurred over the contralateral parietal region, in deaf Ss the effects were also observed over the occipital regions of both hemispheres. In addition, lateral asymmetries in behavior and the ERPs indicated a greater role for the right hemisphere in this task in hearing Ss, but predominance of the left hemisphere in deaf Ss. These results suggest that auditory deprivation since birth has major effects on the development of the peripheral visual system. The specific pattern of group differences is discussed in relation to other studies of the effects of unimodal deprivation on the development of remaining modalities.