BackgroundSociety demands a university education grounded on ethical principles. Education in ethics values is responsibility of universities but will not be viable unless also adopted by directly responsible agents, the teachers who work with the students. For this reason, our primary research objective was to conduct an in-depth analysis of how Health Sciences students self-perceive the ethical dimension.MethodsA mixed research methodology with two phases, qualitative and quantitative, allowed us to address our research question from two complementary viewpoints. Conversational interviews were conducted in an intentional and purposive sample to identify a wide range of discursive representations. A questionnaire was designed based on previous studies and the topics of qualitative research. The response format for the questionnaire followed a Likert scale and modulators such as sex, age, degree and the score of a social desirability test were examined.ResultsAfter 24 conversational interviews, three main thematic blocks (coinciding with the three subscales of the questionnaire) were identified: “attitudes for harmony in human relations”, “construction of the self” and “rules and regulations”. A total of 246 students completed a questionnaire with 39 items. The total scores ranged from 93 to 152 points, with an average score of 122.72 ± 10.64 points. Responsibility, the basic rules of education and respect were perceived as the two most important values, whereas solidarity and social participation as the least important. Results showed a significant positive linear correlation between total score on the questionnaire and age and social desirability. Age was also a significant predictor for the total score and the subscale score “rules and regulations”. The students´ responses seemed to be conditioned by the degree of social desirability that they present.ConclusionsThe ad-hoc questionnaire captured the maintenance of high ethical values in our college undergraduate students, which may be directly related to enhanced social desirability. The scores obtained on the questionnaire were correlated with the students’ age, which may indicate that values might tend to acquire progressively more importance as students grow older. Further research is warranted to delve deeper on the determinants of professionalism and ethical decision-making in college students.Electronic supplementary materialThe online version of this article (10.1186/s12909-018-1396-7) contains supplementary material, which is available to authorized users.