Soft tissue sarcomas are rare malignant tumors. Primary angiosarcomas of the breast account about 0, 04% of all malignant breast tumor cases. We present the case report of simultaneous development of primary angiosarcoma of the breast in the in 22 years old twins. The histological examination of the core biopsy specimen revealed the evidence of angiosarcoma. Each of the patients were treated with combined therapy. In one of the sisters, the tumor mass occupied almost the entire breast, wherefore the first phase Chemotherapy (CT) was administered 5 cycles of gemcitabine and docetaxel. Subsequently the mastectomy with simultaneous breast reconstruction was performed on the right side. Postoperatively another 3 cycles of CT were carried out according to the above described regimen. In the second patient, due to the small tumor size (less than 5cm), the skin-repairing mastectomy with simultaneous breast reconstruction was performed. 6 courses of adjuvant CT was given according to the specified regimen. The genomic analysis of both patients, revealed the germline mutation A518A (C.1782A/T) in the exone-10 and the polymorphism V269V (c.4035T/C) in the exone-11 of the BRCA2-genes. In addition, the polymorphism Int3dupl6 was found in the third introne of the TP53-gene. The same mutation (A518A (C.1782A/T) was also detected in the twin's father. There was no PD after the 12 months of follow-up.