To advance oncology nursing science and clinical practice, researchers and clinicians must understand the important real-world concerns of nurses who provide direct care to people with cancer or manage processes that support patient care. This study developed a comprehensive compendium of real-world concerns among oncology nurses and built consensus regarding their importance. Using Delphi survey methodology, this prospective, descriptive study was performed in 3 phases: (1) identification of experts, defined as registered nurses (RNs) employed within a comprehensive cancer center; (2) qualitative content analysis of 353 responses from 267 RNs who responded to the question, "What do you see as nursing research concerns, problems, and/or issues on your unit or in your work environment that needs to be studied?"; and (3) rating the importance of 62 research themes identified from the qualitative content analysis (n = 247 RNs). The top research priority was patient safety followed by patient education, oncologic emergencies, patient expectations and adherence with care, team communication, patient psychosocial needs, patient-reported outcomes and quality of life, healthcare team burnout, workload, and nurse burnout. The findings support the nursing discipline's fundamental focus on patient safety, the top-rated nursing research priority, along with other patient-related and work environment issues. Oncology nursing is complex and complicated. This study identified and prioritized the real-world concerns, issues, and problems of oncology RNs who provide direct care or manage the processes that support care, supporting the need to focus on patient-related and work environment research.