Recurrence of breast cancer can present in very small tumors even 20 years after initial treatment. Periodic revision of all the operated population during a long time will be necessary to detect all the recurrences. For this the cost-benefit relation of follow-up in breast cancer is a controversial topic. We present our results in 750 cases of breast cancer operated from 1980 and submitted to a follow-up protocol during five years. We analyzed the value of follow-up for the discovery of metastases, local recurrence after conservative treatment and after mastectomy. Finally we considered the usefulness of early diagnosis of familial breast cancer and cancer in the contralateral breast. Metastases was discovered in asymptomatic patients in 68%, which could improve the survival. Recurrence after mastectomy was seen in 1.3% of the patient and a half of these after treatment presented survival superior to 3 years. Follow-up favours early diagnosis and could have influence on survival.