The fixation in ethanol or formalin for trypsin digestion in immunohistochemical detection of cytokeratins and vimentin was assessed in a case of ovarian cystadenofibrocarcinoma. Superior reactivity for both markers was achieved in ethanol-fixed sections, even in samples stocked up to 60 days. Cytokeratin reaction in formalin-fixed sections was better when trypsin was used. However, this digestion was deleterious to vimentin detection. These data are presented to alert surgeons and oncologists on the relevance of fixation of specimens suspicious for neoplasia, since different epitopes may require different fixatives and the inadequate choice in the operative room may impart difficulties when immunohistochemistry is necessary.