The aim of this study was to evaluate the protective effect of concomitant leuprolide treatment on ovarian function in young women undergoing adjuvant chemotherapy for early breast cancer. 19 women, median age 36.5 years (range 26-40 years), with operable breast cancer and negative hormonal receptors, received six cycles of FEC 100 regimen as adjuvant chemotherapy and co-treatment with leuprolide. Menstrual resumption was gained in all patients in a median time of 5 months (range 3-8). Follicle-stimulating hormone and estradiol assessment was performed in all patients. The return to pre-menopausal values was achieved within 6 months of the last leuprolide administration. At a median follow-up of 3 years (range 1-5 years), no patient relapsed and four full-term pregnancies were recorded in four women, each of whom delivered a healthy infant. Our data are in agreement with similar experiences and confirm the activity of GnRH therapy in preventing ovarian failure.