We developed a rapid immunohistochernical method using a microwave oven in formalin-fixed, paraffin-embedded sections from normal and pathological tissues. The strongest immunoreactivity was obtained for actin, Ca 125, CEA, pan-cytokeratin, chromogranin A, EMA, GFAP, thyroglobulin, kappa and lambda chains. In control tissues, processed with conventional immunocytochemical procedure, the reactivity was found to be qualitatively and quantitatively similar. Dako EPOS kits were also assayed with good staining intensity, shortening the original technique to 16 min. Our microwave immunohistochemical method is simple, rapid and it may be recommended for use in routine laboratories.