Widely publicized errors associated with chemotherapy catalyzed extensive efforts to improve safety for patients receiving traditional intravenous chemotherapy. However, an increasing number of cancer patients are prescribed oral chemotherapy, and a prior study found that most cancer centers lack formal safety protocols for these medications. This AHRQ-funded analysis used multiple data sources to identify and characterize oral chemotherapy medication errors, and found that most errors resulted from dispensing incorrect dosages or medications—similar to prior studies of outpatient chemotherapy errors. The authors conclude that standardized safety practices for oral chemotherapy are urgently needed.