Objective: This study aimed to develop and validate the contents of the Mosaico de Opinioes Sobre o Aborto Induzido (Mosai), a structured questionnaire intended to be used as a tool to collect information about the views of health professionals about the morality of abortion. Methods: The contents of the first version of the questionnaire was developed based on the technique of thematic content analysis of books, articles, films, websites and newspapers reporting cases of abortion and arguing about their practice. The Mosai was composed of 6 moral dilemmas (vignettes) related to induced abortion, whose outcomes should be chosen by the respondents and could be justified by the classification of 15 patterns of arguments about the morality of abortion. In order to validate its contents, the questionnaire was submitted to the scrutiny of a panel of 12 experts, an intentional sample consisted of doctors, lawyers, ethicists, sociologists, nurses and statisticians, who evaluated the criteria of clarity of writing, relevance, appropriateness to sample and suitability to the fields. These scores were analyzed by the method of concordance rate, while the free comments were analyzed using the analysis technique content. Results: All the moral dilemmas and arguments were considered valid according to the rate of agreement, however, some comments led to the exclusion of a dilemma about emergency contraception, among other changes. Conclusion: The content of Mosai was considered valid to serve as a tool to collect the opinions of healthcare professionals regarding the morality of abortion. (C) 2013 Elsevier Editora Ltda. All rights reserved.