A report on 1877 consecutive node negative (N-) breast cancer cases is presented in which the prognostic value of the main clinico-pathologic features is evaluated. Tumor size (and UICC-TNM T category) and lobular infiltrating histologic type were significantly associated with a more favorable prognosis whereas no association was found for patient age, tumor site and number of examined axillary nodes. However tumor size (and T category) is not a very accurate prognostic predictor (71% of all recurrences observed occurred in cases with tumor diameter of more than 20 mm, which represented 58% of the total series), although its efficiency seems almost as good as that of other more recent prognostic predictors such as estrogen receptor content or labeling index. None of the prognostic predictors currently available, including tumor size, seems sufficiently specific and they do not allow for a reliable selection of high risk N-patients for adjuvant treatment.