Data of 45 patients, who underwent pancreaticoduodenectomy and regional lymphadenectomy for ductal adenocarcinoma of the pancreas, were reviewed in a retrospective study. Carcinomas of the papilla of Vater, the distal common bile duct and the duodenum were excluded. Tumors were classified according to the TNM staging (UICC 87) and Kloeppel’s histomorphological grading. DNA content was measured in each tumor by cytophotometry. DNA analysis revealed 11 ‘triploid’ and 34 ‘nontriploid’ tumors. No tumor was located in the ‘diploid’ region. The clinical course of triploid tumors was significantly more malignant than that of nontriploid tumors (p ≤ 0.005). No difference could be found in the outcome of the individual staging and grading groups. An important advantage of DNA analysis in the assessment of prognosis is its objectivity and the possibility of pretherapeutic examination of small biopsy specimens or fine needle aspiration