Introduction: This study investigated the efficacy of fulvestrant in premenopausal patients with metastatic breast cancer who developed artificial menopause using a luteinizing hormone releasing hormone analogue. Methods: This retrospective study was conducted at the Istanbul Okmeydani Education and Research Hospital. Results: A total of 37 patients were evaluated, with a median age of 39 years old (range 27__ampersandsignndash;49) and a median follow-up time of 20.2 months (0__ampersandsignndash;78). Of these patients, 86.5% had invasive ductal carcinoma, 5.4% had invasive lobular carcinoma. Bone metastasis was found in 83.8% of the patients, lung metastasis in 21.6%, lymph node metastasis in 16.2%, liver metastasis in 13.5%, and brain metastasis in 5.4%. The progression-free survival (PFS) was a median of 12 months after starting the fulvestrant. The PFS was relatively shorter in those with brain metastases, but there was no statistically significant difference. The median PFS was 12 months in 2 series and 8 months in 3 and later series, which was statistically significant (p=0.025). The overall survival (OS) was a median of 77 months; it was 86% at 12 months, 63% at 36 months, and 56% at 60 months. The median OS of the 2nd line was 20 months. No grade 3-4 toxic effects were observed. Conclusion: As in naturally postmenopausal patients, fulvestrant was found to be effective and tolerable in patients treated with artificial menopausal hormone receptor-positive metastatic breast cancer under the age of 50. The fulvestrant was more effective in those who did not previously receive hormonal therapy.