In this study we analysed DNA-ploidy as a potential prognostic parameter in ductal pancreatic carcinoma. Paraffin embedded histological material, obtained by resection from 34 patients with a ductal pancreatic carcinoma, was selected for analysis. Tumor areas within the paraffin embedded material were identified by HE-stained reference sections. One 50 microns section was dewaxed, rehydrated and mechanically and enzymatically prepared to form a suspension of 10000 cells/ml. One milliliter of the suspension, which contained bare nuclei with small rests of cytoplasma, was centrifuged on glass slides. The fixed nuclei were air-dried and stained by Feulgen SITS technique, which allows for the quantitative measurement of DNA. The DNA analysis was carried out with a computer-controlled single-cell cytophotometry. In contrast to using flow cytometry, only the tumor cells were measured by image-cytometry. Overlapping nuclei, dirt and other artifacts as well as inflammatory cells were efficiently eliminated. With DNA image-cytometry, we could differentiate between hypotriploid, triploid, hypertriploid and tetraploid tumors. The DNA-content provided the strongest influence on prognosis in the multivariate analysis.