The authors report on 4,034 consecutively operated breast cancer cases, evaluating the correlation between clinical T category and long term survival. Age and pathologic nodal status were also considered as independent prognostic factors. Univeriate and multivariate (Cox's) analysis confirmed N status as the most powerful single prognostic indicator and did not reveal any prognostic correlation with age. T category was a strong prognostic indicator, independently of N status, the 10 year overall survival of T1, T2 or T3-4 cases being 0.86, 0.76 and 0.73 in N- and 0.73, 0.56 and 0.35 in N+ subgroups respectively. T category should be carefully considered not only in deciding the extent of surgical excision but also in planning adjuvant postoperative treatment.