Five hundred and seventy cases in 252 reports of the delusion of substitution yielded 200 cases with an organic contributor to the occurrence of the delusion. In 79 cases lateralization or localization could be determined, with lesions primarily in the left temporal or right frontal areas. Factors related to ‘feature recognition’, ‘familiarity’ and ‘reduplication’ could be found and are discussed in relation to the neurobehavioral features of the symptom.