Background: Studies that capture the patient’s point of view, including the patient’s perception and experiences, are more and more demanded and valued by health authorities. To design such studies in a timely and cost-effective manner, it is crucial to take into account local regulations, (as they vary a lot across countries), as well as the possible requirement of scientific journals for Ethics Committee (EC) approvalMethodology: Documentary Method – critical analysis of country specific legislation; critical analysis of journal / editor recommendations on Ethics Committee opinion. Results: Observational studies collecting patient reported outcomes and patients’ preferences and perceptions of their disease or treatment require a formal approval from a single Ethic Committee (EC) in Spain. In France, as long as patients are involved in the study, EC approval is mandatory unless the study falls into the category of social sciences health research. In Italy, all observational studies other than prospective cohort studies require EC notification. In Switzerland, Swissethics states that, under cantonal and federal legislation, these studies do not require EC review. Conclusions: For a given patient-based study, the EC processes to be followed clearly differ across European countries. The associated time and budget to be anticipated for EC review may range from zero to several months and several thousand Euros. In addition, journals may base their requirement for EC review on their own national standards instead of country specific regulations. Considering this situation, and to avoid any pitfalls, it is highly recommended to seek for ethics opinion from an Independent Review Board, even if local regulations do not impose EC review. Therefore, investigators are well advised to seek guidance from local Ethics committees and anticipate the publication strategy before the study start.