Background Doctors often deal with end-of-life issues other than assisted death, such as incompetent patients and treatment withdrawal, including food and fluids. Methods A link to a questionnaire was sent by email three times, at one-week intervals, to the doctors registered in the Northern Section of the Portuguese Medical Association. Results The questionnaire was returned by 1148 (9%) physicians. This study shows that only a minority of Portuguese doctors were willing to administer drugs in lethal doses to cognitively incompetent patients (...) at the request of a family member or other close person, and even less would do it on their initiative. Most doctors favored the withdrawal of life support measures in advanced and progressive diseases at the patient’s request. Still, much fewer doctors agreed with the suspension of supportive life measures at the request of a family member, another close person, or by their own unilateral decision. However, fewer agreed with that action concerning the rest of the food and fluids. Portuguese doctors favor the administration of drugs for suffering control, even foreseeing they could shorten life. Conclusion Most doctors in this study respect patients’ autonomy but disagree with measures decided by others that have an impact on patients’ survival. They also agree with the administration of drugs for suffering control, even considering the possibility of shortening life. (shrink)