Phase 1 clinical trials are essential to improving outcomes in cancer care. The investigational agents in these trials may be associated with adverse events that can contribute to symptom burden and declining performance status for trial participants. The emerging role for oncology nurse practitioners (ONPs) as subinvestigators offers a unique practice setting for advanced practice nurses. In this role, ONPs provide expert oncology care, are responsible for swift recognition and management of adverse events, and ensure adherence to the clinical trial protocol.