Panic attacks can be observed in a wide range of situations, but most common are those providing complex and unstructured stimulations, suggesting an impairment in attentional processing of visuo-spatial information. This study evaluated agoraphobics' attentional processing of neutral (i.e., not anxiety-provoking) visuo-spatial stimulation. Twelve patients suffering from panic attacks with agoraphobia were compared with 22 normal controls on a computerized visual target discrimination task specifically designed for this study. Psychometric measures assessed the phobic avoidance, the level of depression and anxiety. The numbers of errors and reaction times were analysed with a three-way ANOVA (Group x target modality x number of stimulations). No between-group significant difference was found for the reaction time performance and the mean number of detection errors. However, an interaction effect was observed for this last variable depending on the target modality: agoraphobic patients made fewer omission errors than control subjects when the target was present among distractors, while they made more commission errors when the target was absent. Outcomes are discussed in terms of attentional hyperactivation related to anxiety and perseverative decision process in agoraphobic patients.