Background Evidence suggests that healthcare professionals feel inadequately equipped to manage ethical issues that arise, resulting in ethics-related stress. Clinical ethics consultation, and preventive ethics strategies, have been described as ways to decrease ethics-related stress, however information is limited regarding specific sources of ethical concern. Methods The purpose of this study was to conduct a retrospective, longitudinal analysis of a comprehensive database of ethics consultations, at a major academic medical center in the Northeast United States in order to: (1) Discern major sources of ethical concern, (2) Evaluate how these have changed over time in their content and frequency, (2a) Evaluate trends in nurse versus physician-initiated requests. Results Six major reasons for requesting an ethics consult were identified: Conflict Over Goals of Care, Decisional Capacity, Withholding/Withdrawing Treatment, Proxy Decision Making, Communication, and Behavior. Themes were operationally defined by the study team. An increase in requests related to Conflict Over Goals of Care (β = 0.7, 95% CI = 0.2–1.2, p = 0.008) and Discharge Planning (β = 2.2, 95% CI = 1.4–3.1, p < 0.001), and a trend toward increased number of consults for behavior-related consults from nurses (median 6.5% versus 2.3%, p = 0.07) were noted. Nurses were significantly more likely than physicians to request ethics consultation for Communication (yearly median 10.4% of cases vs 1.3% of cases, p = 0.01), whereas, physicians were significantly more likely to request ethics consultation for Proxy Decision-Making than nurses (yearly median 26.0% of cases vs 13.0%, p = 0.005) and for Decision-Making Capacity (yearly median 7.5% of cases vs 4.0%, p = 0.04). Conclusions This study revealed several noteworthy and previously unidentified trends in consultation requests, and several important distinctions between the sources of ethical concern nurses identify versus those physicians identify. These findings can be used to develop future preventive-ethics frameworks.