Measurement of DNA ploidy can be performed either with Flow Cytometry (FCM) and Image-Analysis (IA); both methods provide prognostic information in primary breast cancer. We compared the results of quantitative DNA analysis of formalin fixed, paraffin embedded tissue from 62 invasive ductal breast cancers. For FCM nuclear suspensions from disaggregated tumor were stained with Propidium Iodide and analyzed by means of Ortho Cytoron Absolute. For IA nuclear suspensions were stained by the Feulgen method and analyzed by means of Vidas system. We found a good correlation between flow cytometry DNA Index and Histogram Type, according to Auer classification (rs = 0.65, p < 0.001) and between DNA Index and Grading of Malignancy (MG) which had been measured by Bocking's algorithm (rs = 0.38, p < 0.05). Concerning to disease free survival (DFS), flow cytometric DNA Index showed a better correlation (rs = 0.56, p < 0.001). We concluded that the two methods provide comparable results, but offer individual advantages and are complementary for analyzing DNA ploidy in breast cancer.