Oncology clinical trials are important in the improvement of outcomes for people with or at risk for cancer. Because of the complexity of oncology clinical trials and the needs of patients with cancer, nurses play a crucial and unique role in the trial setting. However, great variability exists in how the role of the nurse on a research team is defined and implemented. An Oncology Nursing Society project team set out to identify the core competencies required of a novice oncology clinical trials nurse (CTN) across diverse settings. This article describes the process used to develop core competencies for the novice CTN, presents the final core competencies, and offers examples of how those competencies might be used in practice.