Pregnancy-associated breast cancer (PABC) is malignant neoplasm of the breast diagnosed during pregnancy or up to one year after delivery. Triple negative breast cancer (TNBC) is more common in patients younger than 50 years and has a more aggressive character. The treatment of PABC should consider the type of tumor, the stage of the disease, the gestational age at the time of diagnosis and the wishes of the patient and family members. The firstline treatment, due to the contraindication to radiotherapy during pregnancy, is radical mastectomy. Chemotherapy drugs are contraindicated in the first trimester and outside this period, their use must be carefully and discussed. Breast tumors found in pregnant women, in addition to being diagnosed in more advanced stages, are often more aggressive, of the triple negative type, demonstrating the relevance of the association of both for discussion. For this reason, the present study aims to report 3 cases of young patients diagnosed with breast cancer associated with triple negative pregnancy.