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Executive functioning is classically described as a range of high-level cognitive processes that can be clearly dissociated and that are localized in frontal areas. However, a series of data in patients with acquired brain lesions led to a questioning of this conceptualization. In this context, we administered a large battery of executive and attentional tasks to a small group of brain-damaged patients (N=9) to determine, with multiple cases analyses, the influence of the lesion size and localization, and the influence of attentional difficulties on the occurrence of a dysexecutive syndrome. The analyses of the individual profiles of our patients seem to indicate that an inefficient transfer of information between anterior and posterior cerebral areas is responsible for the occurrence of executive dysfunction and that, for some patients, attentional difficulties determine this dysfunction. However, the damage of specific (and relatively focal) key-areas responsible for general cognitive processes (i.e., short term memory) involved in a large range of executive tasks is responsible for the occurrence of a large executive dysfunction. Our results are also in agreement with the separability of executive processes, as we observed double dissociation in some of our patients between inhibition and flexibility preserved/altered capacities. However, we similarly observed an important heterogeneity in the patterns of preserved/altered performance within functions considered as unitary (double task coordination and flexibility).