Delusions of parasitosis (DOP) is a psychiatric disorder in which people have an unshakable false belief that they are infested with arthropod parasites. To rid themselves of the "bugs" patients with DOP may become desperate and quit their jobs, burn furniture, abandon homes, and use pesticides dangerously and repeatedly. Data from 11 cases of DOP, reported to the Mississippi Department of Health between 1989 and 1993, are presented in an attempt to identify common factors among the cases. Seven of the 11 patients (64%) were elderly white women. Five patients complained of "mites," 3 of "insects," and 3 of "bugs"; and all characteristically offered "proof" of their infestation such as bits of debris or skin scrapings wrapped in paper or in tiny jars. Only one complained of itching. Six patients reported extensive use of pesticides. These results elucidate the clinical presentation of DOP cases, thus aiding in diagnosis of the disorder.