BACKGROUND: Lack of faculty training is often cited as the main obstacle to post-graduate teaching in communication skills. Aims: To explore clinical supervisors' needs and perceptions regarding their role as communication skills trainers. METHODS: Four focus group discussions were conducted with clinical supervisors from two in-patient and one out-patient medical services from the Geneva University Hospitals. Focus groups were audio taped, transcribed verbatim and analyzed in a thematic way using Maxqda software for qualitative data analysis. RESULTS: Clinical supervisors said that they frequently addressed communication issues with residents but tended to intervene as rescuers, clinicians or coaches rather than as formal instructors. They felt their own training did not prepare them to teach communication skills. Other barriers to teach communication skills include lack of time, competing demands, lack of interest and experience on the part of residents, and lack of institutional priority given to communication issues. Respondents expressed a desire for experiential and reflective training in a work-based setting and emphasised the need for a non-judgmental learning atmosphere. CONCLUSIONS: Results suggest that organisational priorities, culture and climate strongly influence the degree to which clinical supervisors may feel comfortable to teach communication skills to residents. Attention must be given to these contextual factors in the development of an effective communication skills teaching program for clinical supervisors.