AKI is common in patients with cancer, and it causes interruptions in therapy and increased hospital length of stay, cost, and mortality. Although cancer patients are susceptible to all of the usual causes of AKI in patients without cancer, there are a number of AKI syndromes that occur more frequently or are unique to this patient population. AKI also confers substantially increased risk of short-term death, and the ability to reverse AKI portends a better outcome in some cancers, such as multiple myeloma. Several trends in oncology, including increased survival, better supportive care, older patients who have received multiple chemotherapy regimens, and new therapeutic options, are driving an increase in the numbers of cancer patients who develop AKI. As a result, nephrologists should be increasingly familiar with the diagnosis, management, and treatment of AKI in this setting. Here, we summarize recent data on epidemiology of AKI in cancer patients, describe the most common AKI syndromes in this population, and highlight emerging areas in the growing field of onconephrology.