Purpose: To investigate the opinions of Brazilian medical residents in Obstetrics and Gynaecology on abortion legislation according to their personal beliefs. Material and methods: A multicentre cross-sectional study. Residents at 21 university teaching hospitals completed a self-report questionnaire on their opinions in abstract terms, and about punishing women who abort in general and women they know. Results: In abstract terms, 8% favoured allowing abortion under any circumstances (fully liberal); 36% under socioeconomic or psychological constraints (broadly liberal); 75.3% opposed punishing a woman who has aborted (liberal in general practice); and 90.2% opposed punishing women they knew personally (liberal in personal practice). Not having a stable partner and not being influenced by religion were factors associated with liberal opinions. In personal practice, however, 80% of those who are influenced by religion were liberal. The percentage of respondents whose opinions were liberal was significantly greater among those who believed that abortion rates would remain the same or decrease following liberalisation. Conclusions: Judgements regarding the penalisation of women who abort are strongly influenced by how close the respondent is to the problem. Accurate information on abortion needs to be provided. Although about one third of the respondents were broadly liberal, the majority oppose punishment.