A technique which includes the use of indirect immunoperoxidase antibody (IPA) has been developed for detecting enteric adenovirus and rotavirus antigens in cell cultures and has been compared with immunofluorescence antibody assay (IFA). The IPA technique was as sensitive as the IFA. The number of positive cells detected by both techniques in tissue cultures was the same; false positive results were not observed. The applicability of IPA in clinical virology is discussed.