Post-recurrence survival was examined in 62 breast cancer patients who had undergone curative radical mastectomies between 1974 and 1976 and suffered recurrences within 127 months of surgery. The prognostic value of 11 clinical, histological and genetic factors, including histologic grade of malignancy and amplification of oncogenes was analyzed using univariate and multivariate analyses. Not only the site of first recurrence, clinical stage and size of primary tumor at initial surgery, and disease-free period, but also histologic grade and amplification of the c-erbB-2 proto-oncogene were significant prognostic indicators of recurrent breast cancer. Multivariate analysis using Cox's regression model, histologic grade and amplification of c-erbB-2 in the primary tumor, as well as clinical stage at surgery and site of first recurrence, were shown to be major independent prognostic factors of recurrent breast cancer. Because post-recurrence prognosis was strongly influenced by the clinical, histological and genetic status of the primary breast cancer, appropriate evaluation of the primary tumor for the grade of aggressiveness of the cancer cells, as well as the extent of cancer spread, seem to be important.