Introduction: Bioethics subject which is part of the curriculum in higher education has a slightly different orientation compared to the science subjects. This study investigates the challenges of teaching bioethics subject to the health sciences students and the outcome of using mixed educational background classes in bioethics. Methods: Discussions among lecturers of bioethics were conducted to determine the possible challenges when teaching bioethics to the health sciences students who are accustomed to the format of science subjects. Results of written bioethics tests (multiple choice questions [MCQs] versus short essays) were also analysed among students from nine different health sciences background (biomedical sciences, nursing, speech pathology, dietetics, nutrition, medical radiation, audiology, sports science, and occupational safety and health) as a measure of the students’ understanding of the bioethics subject. Findings: The challenges of bioethics teaching were divided into five categorical themes; (i) attitude/discipline, (ii) background knowledge, (iii) reasoning/critical thinking, (iv) knowledge/jargon, and (v) diverse educational background. Excellence performances were demonstrated by the students across the ten disciplines in the direct MCQs while they did very poorly (p < 0.01) in the critical thinking short essay questions. Conclusions: Bioethics proof to be a challenging subject for the health sciences students as this subject deal with complex issues of ethical concerns which differ with most science subjects. Combined efforts of the educators and students are needed in order to address these challenges and stimulate the understanding of bioethics.