AbstractA simple method of labeling 3 antigenic sites on 1 tissue section with only the conventional immunoperoxidase method is described. Although procedures to label 3 or more antigens simultaneously have been reported previously, they have used combinations of fluorescence, immunoperoxidase, and alkaline phosphatase to produce chromagens of different colors. The triple-label imrnunoperoxidase procedure described is both cost- and time-effective, yields permanent results, and offers distinct advantages over other staining procedures. (The J Histotechnol16:121, 1993)