A general problem in immunocytochemistry is the development of a reliable multiple immunolabeling method with primary antibodies originating from the same host species. Here, we briefly outline different approaches intended to close this technological gap and focus on multiple immunolabeling with monoclonal primary antibodies. To this end, we generated a basic universal protocol for the use of secondary antibodies selectively recognizing different isotypes/subclasses of monoclonal primary antibodies. This approach is widely applicable and offers a simple procedure for simultaneously detecting two or more antigens.