The central feature of misidentification syndromes is the presence of a delusion in which either the identity of the self or other persons is misrecognized. Recent psychiatric case reports have noted the dangerousness posed by persons with misidentification delusions. The authors report on a series of 29 individuals whose delusional misidentification was associated with aggressive behaviors. Important parameters which may assist in defining this sample of dangerous delusional misidentification syndrome persons are discussed.