Attention and memory dysfunction is a common complaint among patients with breast cancer that can be reported during and up to several years after treatment. It can negatively affect patients' quality of life and their ability to work. This phenomenon has mainly been studied in patients with breast cancer who are treated with adjuvant chemotherapy. Women describe concentration problems and difficulties with word finding, multitasking, or remembering new information, as well as more effort and time needed to accomplish these tasks. Such cognitive dysfunction is subtle or moderate and occurs in 15% to 25% of patients. Older patients seem more likely to experience cognitive decline with chemotherapy than do young women with breast cancer. Patients who report that cognitive dysfunction has affected their daily lives for 6 to 12 months after the end of chemotherapy or during hormone therapy may need referral to a neuropsychologist. During the cognitive assessment, the etiology of their cognitive complaints is sought and neuropsychological tests are administered to assess objective cognitive functioning. Psychological factors-fatigue and pain-should be assessed systematically with cognitive complaints to identify precisely the cause of the problems. A nonpharmacologic approach-mainly cognitive rehabilitation-seems to be the most promising for the management of these difficulties, but these preliminary results require confirmation. In the future, early detection of cognitive impairment and cognitive rehabilitation should be included in the portfolio of oncology supportive care to facilitate the return to work of young women and to avoid potential repercussions on adherence to oral treatments and on autonomy in older patients.