We describe a method in which microwave irradiation is used to reduce substantially the incubation time for immunoperoxidase staining of antigens in cryostat sections of psoriatic skin. An incubation time of 5-9 min irradiation at 80 W generated similar or better staining intensity for all antibodies used compared to the standard methods using 30-60 min incubation at room temperature. Although we found that microwave irradiation could be used with all antibodies tested, independent of whether they recognized extracellular, membrane or cytoplasmic antigens in skin, the conditions needed to be optimized for each antibody.