CONTEXT Research activity is not a mandatory component of medical education in many developing countries, including Brazil, although such experiences can have a positive impact on the quality of medical education. The interest and involvement of medical students in research and the barriers they face in accessing research training in developing countries have not been adequately addressed. OBJECTIVES We sought to assess the availability of scientific training programmes in Brazilian medical schools, the degree of involvement of medical students in these programmes, the main barriers to student involvement in research and possible reasons for the lack of scientific training programmes. METHODS This study examined 13 medical programmes conducted in six Brazilian states. A total of 1004 medical students were interviewed. We evaluated the availability of scientific training in the institutions attended by these students, the participation of the students in such activities and students’ reasons for not joining such programmes based on student answers to our questionnaire. RESULTS Although only 7% of the medical students expressed no interest in research, only 60% of them were involved in research training. Students regarded a lack of institutional incentive as the most significant barrier to their participation in research activities. Other significant barriers included defective infrastructure and insufficient time available for professors to mentor undergraduate students. According to the feedback from the students, eight of the 13 schools investigated featured structured programmes for scientific training. However, a mean of only 47% of students participated in scientific training programmes on their campuses and 13% of students were compelled to pursue such activities off-campus. CONCLUSIONS Although scientific training during medical education in Brazil is still less frequent than expected, most of the students were interested in research activities. The barriers to undergraduate scientific training described in this paper may help the Brazilian government improve research training in medical schools. These issues might also be explored in other developing countries.2030-01-01