From January, 1988 to October, 1995, 96 patients with operable breast cancer were treated by breast conserving treatment (BCT) including wide excision and axillary dissection followed by breast radiation. During the same period, 188 patients were treated by modified radical mastectomy (MRM) with or without breast reconstruction. In order to compare the survival of BCT and MRM groups, univariate and multivariate analyses were performed in this retrospective study. Univariate analysis revealed that the 5-year survival rates in the BCT and MRM groups were 97% +/- 2% and 87% +/- 3%, respectively (p < 0.05 with the Cox-Mantel test). However, the baseline variables were different between the groups. The adjusted Cox regression analysis revealed that the results of BCT were almost equivalent with those of MRM. Moreover, no breast recurrence was found in the BCT group. Therefore, it is suggested that our technique of BCT is as effective as modified radical mastectomy in treating operable breast cancer in Japanese patients.