The　influence　of　spatial　congruency　on　audiovisual　interaction　in　a　visual-attention　task　in　which　only　the　visual　segment　of　a　bimodal　audiovisual　stimulus　was　required　to　attend　was　investigated　using　behavioral　and　electrophysiological　measures　in　humans.　The　behavioral　results　showed　that　the　responses　to　audiovisual　target　stimuli　were　faster　than　that　to　unimodal　visual　target　stimuli.　Moreover,　we　recorded　event-related　potentials　(ERPs)　to　unimodal　visual　stimuli,　unimodal　auditory　stimuli,　spatially　congruent,　and　incongruent　bimodal　audiovisual　stimuli.　The　audiovisual　interaction　effects　were　detected　by　comparing　the　ERPs　to　audiovisual　stimuli　with　the　sum　or　the　ERPs　to　unimodal　visual　and　auditory　stimuli.　The　ERPs　results　showed　audiovisual　interaction　were　detected　as　a　negativity　in　mid-central　scalp　sites　at　around　a　latency　of　300　ms　during　the　later　stage　of　processing　under　both　a　spatially　congruent　condition　and　incongruent　condition.　But　the　amplitude　around　300ms　was　significantly　larger　than　that　under　a　spatially　congruent　condition.　Thus,　audiovisual　interaction　depends　on　the　spatial　congruity　of　the　bimodal　audiovisual　stimuli.　©2009　IEEE.