Cotherapy teams are formed for a variety of reasons by clinicians who vary in their degree of training and experience. Looking at why cotherapy teams are formed provides a basis for understanding the dynamics of the team and how the leadership pairing affects the group. In the case of the collaboration of two seasoned clinicians, cotherapy can enrich the therapeutic opportunities for a group as well as provide the therapists with the experience of working with colleagues who share the same clinical or research interest. It is the unique dynamics of the senior-senior cotherapy team that will be the focus of this paper. For the purpose of discussion, a senior therapist is defined as having formal training in group psychotherapy and at least five years of experience in conducting shortor long-term groups as a solo facilitator.