In the search for new therapeutic alternatives against cancer, either as a preventive treatment or for advanced stages, it is common to appeal to well-known drugs used for the treatment of other diseases that may interfere with the metabolic pathways involved in carcinogenesis. Non-steroidal anti-inflammatory drugs (NSAIDs) display anticancer activity through the inhibition of the COX-2 enzyme, triggering processes such as apoptosis, a reduction in proliferation and inhibition of carcinogenesis. Breast cancer is a neoplasm with the highest incidence and mortality rate among young women worldwide. Epidemiologic data have shown that drugs such as NSAIDs, particularly aspirin, reduce the relative risk of breast cancer. However, in the subgroup of responsive patients, dose, time and frequency of use have not yet been established. Here, we review the reports published during the last 10 years regarding the relationship between breast cancer and aspirin.