Objective: To survey members of the American Society for Bioethics and Humanities (ASBH; n = 327) and of the Society for Medical Decision Making (SMDM; n = 77) to elicit the similarities and differences in their reasoning about two clinical cases that involved ethical dilemmas. Cases: Case 1 was that of a patient refusing treatment that a surgeon thought would be beneficial. Case 2 dealt with end-of-life care. The argument was whether intensive treatment should be continued of an unconscious patient with multiorgan failure. Method: Four questions, with structured multiple alternatives, were asked about each case: identified core problems, needed additional information, appropriate next steps and who the decision maker should be. Observations and results: Substantial similarities were noticed between the two groups in identifying the core problems, the information needed and the appropriate next steps. SMDM members gave more weight to outcomes and trade-offs and ASBH members had patient autonomy trump other considerations more strongly. In case 1, more than 60% of ASBH respondents identified the patient alone as the decision maker, whereas members of SMDM were almost evenly divided between having the patient as the solo decision maker or preferring a group of some sort as the decision maker, a significant difference (p<0.02). In case 2, both groups agreed that the question of discontinuing treatment should be discussed with the family and that the family alone should not be the decision maker. Conclusion: Despite distinctively different methods of case analysis and little communication between the two professional communities, many similarities were observed in the actual decisions they reached on the two clinical dilemmas. [ABSTRACT FROM AUTHOR]