Large-scale cognitive-behavioural Stress Management workshops were run formembers of the general public as part of a city-wide mental health promotioncampaign. Four groups were compared: a workshop run over one day (Full-Day),one run over two half-days (Half-Day), a non-specific intervention controlgroup, and a waiting list control group. Results indicate that theparticipants in the workshop groups improved more than those in either ofthe control groups, supporting the idea that the psychoeducational approachcan be valuable and economical in a health promotion and public healthcontext. The use of this format in clinical situations and in primary caresettings is also discussed.