The attentional blink (AB) refers to an impairment in the report of a second target (T2) if it closely follows the presentation of a first target (T1) in a rapid serial visual presentation (RSVP), when both targets must be reported. In the present study, a modified AB paradigm was used in which targets could appear in any of four simultaneous RSVP streams, one in each quadrant of the visual field. In half of the trials, T1 and T2 were displayed in the same visual hemifield (either left or right) and, in the other half, T1 and T2 were displayed in different visual hemifields. Using this paradigm with both neurologically intact individuals and a split-brain patient, we sought to investigate (1) possible hemispheric asymmetries in attentional processes, and (2) whether the AB would be reduced when targets are displayed in different visual hemifields. A comparable AB was found for both neurologically intact individuals and the split-brain patient, with no significant variations due to whether targets were displayed in the same or in different hemifields. A left hemisphere advantage in the processing of same and different hemifield targets was observed only in the split-brain patient.