Axillary lymph node-negative (pN-) breast carcinomas (n = 281) were analysed histoquantitatively for two mitotic indexes (MAI, mitotic activity index; M/V, volume corrected mitotic index) and nine nuclear factors with special emphasis on disclosing prognostic factors during a follow-up of 12 years. The M/V index (P = 0.0018), tumour size (P = 0.0052), MAI (P = 0.0115) and histological grade (P = 0.0565) predicted the recurrence-free survival. MAI (P = 0.0007), M/V index (P = 0.0046), tumour size (P = 0.0133), histological grade (P = 0.0528) and S.D. of the nuclear perimetry (P = 0.07) predicted the disease-related survival. In Cox's analysis, MAI (P = 0.004), adjuvant therapy (P = 0.03) and tumour size (P = 0.09) predicted survival independently. Recurrence-free survival was related independently to nuclear perimetry (P less than 0.001), SD of nuclear area (P = 0.01) and MAI (P = 0.019) in Cox's analysis. In small (diameter less than or equal to 20 mm) tumours, S.D. of nuclear perimetry predicted recurrence-free survival (P = 0.03) in Cox's analysis. The results advocate the use of mitotic indexes and nuclear factors in place or in combination with conventional histological grading in predicting the survival and tumour recurrence in axillary lymph node-negative breast carcinomas.