Introduction: Breast cancer (BC) is the most frequently-diagnosed life-threatening cancer among women. Despite significant advances in early detection, it remains the second-leading cause of cancer-related deaths among women worldwide. The poor prognosis of most breast cancer patients is mainly due to late diagnosis. Therefore, identification of new biomarkers for early diagnosis in cancer is urgently required. Exosomes are membrane-bound vesicles, 30–100 nm in size, released from various types of mammalian cells upon the fusion of multivesicular bodies with plasma membranes. Emerging evidence shows that exosomes are involved in the development and progression of different tumor types, including breast cancer. Therefore, identification of BC-related exosomes and their underlying mechanisms in progression of BC would be helpful in the early diagnosis of BC and stablishing appropriate therapeutic strategies.Description: to highlight the potential roles of exosomes in tumor initiation, proliferation, migration, invasion, metastasis, and their potential applications in early diagnosis of breast cancer.Discussion and conclusion: Tumor-derived(TD) exosomes exist extensively in biological fluids such as blood, plasma, cerebrospinal fluid, and urine. It has been proved that (TD) exosomes are involved in constructing of a tumor microenvironment that supports the spread of a tumor, invasion and pre-metastatic niche development. In fact, exosomes by restricting of immune control and secretion of growth factors, angiopoietin factors, and cytokines from stromal cells, promote cell migration, cancer progression, and metastasis. In addition, (TD) exosomes are enriched in some specific miRNAs and proteins compared with non-tumorigenic cells and it has been well evidenced that these components play a critical role in the development of BC tumors. Altogether, it seems that breast tumor-derived exosomes can be served as worthwhile, non-invasive diagnostic and predictive biomarkers for early detection of breast cancer.