AIMS--To develop and immunohistochemical staining method for cryostat and paraffin wax sections so that two different antigens in the same section of tissues could be detected by combining immunoenzyme and immunofluorescence techniques. METHODS--This double immunohistochemical staining method combines alkaline phosphatase-anti-alkaline phosphatase (APAAP) using New Fuchsin as a chromogen and indirect immunofluorescence. RESULTS--APAAP staining for one antigen of this double immunohistochemical staining method was observed under bright field conditions alternating with immunofluorescence for another antigen under ultraviolet light. The double exposed photograph of both easily identified the two signals within the same cell. CONCLUSIONS--This double immunohistochemical staining method can overcome the disadvantages of any masking effect of the double immunoenzymatic methods and the background problems of double immunofluorescence method especially when applied to paraffin wax sections. It also permits good morphological identification of the doubly stained cells which may be of crucial importance in studies on pathology specimens.