This study evaluated a training program for leaders of supportive- expressive psychotherapy groups for breast cancer patients. Twenty-four mental health/medical cancer care professionals completed two training phases and were tested for their understanding of the treatment model. Participants' understanding was enhanced as a result of the training program. This study demonstrates that a brief training program can improve therapists' understanding of the treatment model and demonstrates an effective method of evaluation. Future research should examine how performance on these tests generalizes to performance when leading a supportive-expressive group.