Introduction: The growing incidence and recurrence rate of breast cancer has influenced multiple strategies such as surgical interventions that serve as preventive measures for women at high risk. Prophylactic mastectomy seems to be the most effective tool in the primary prevention of breast cancer, but opinions are not uniform, especially among specialists. The goal of this presentation is to examine the effect of risk-reducing mastectomy, including breast cancer incidence, breast cancer mortality, disease-free survival, physical morbidity, and psychosocial outcomes in cohort of patients who underwent prophylactic mastectomy. Materials and Methods: We retrospectively reviewed the outcomes of 20 years of experience with prophylactic mastectomies performed at the department from 1999 to 2019. In this study were included patients who underwent bilateral prophylactic mastectomy with no breast cancer, and patients with breast cancer, if they underwent contralateral risk-reducing mastectomy, however, only the prophylactic side was considered in the analysis. Patients with bilateral breast cancer were excluded. Results: A total of 749 risk-reducing prophylactic mastectomy in 545 patients were performed at our department from 1999 to 2019. Bilateral prophylactic mastectomies were performed in 204 patients (37,4%), and 341 (62,6%) underwent a unilateral risk-reducing mastectomy secondary to cancer in the contralateral breast. Overall, 243 patients with BRCA1 mutations and 113 with BRCA2 mutations were included. Conclusion: Prophylactic mastectomy is highly preventive against breast cancer. Although further clinical studies are needed to determine the effectiveness of prophylactic mastectomies in individual indications. With the effectiveness of prophylactic mastectomy should also be taken into consideration the quality of life after the immediate breast reconstruction, and the associated complications.