The differences in clinical bioethics between the Mediterranean and Latin American cultures have not been analyzed. The objective of the study is to compare the ethical conflicts that internists in Spain, Mexico and Argentina have. Cross-sectional observational study through a survey directed at internists from Spain, Argentina and Mexico. The survey was administered to affiliated members of the National Societies of Internal Medicine across three countries via an online platform. 762 internists participated, 261 from Spain, 154 from Argentina and 347 (...) from Mexico. The main ethical conflicts that internists in Spain, Argentina and Mexico have are related (in order) to the end of life, to the clinical relationship and to the patient’s autonomy. Withholding and withdrawing life-sustaining treatment is the most frequent conflict in Spain and Argentina and the second in Mexico. Internists from Spain and Argentina identify very similar ethical conflicts. Furthermore, they consider them more frequent and difficult than in Mexico. In Argentina they are less satisfied with the way they are resolved. To explain these differences, socio-cultural factors are postulated, among others: paternalism, individualism, masculinity, organization of the health system, formal training in bioethics and assessment of death. (shrink)