This paper notes that the rapid increase in the number of support groups for older persons and for their caregivers necessitates a look at the role of the professional as a facilitator of support groups. It defines the concepts of social support and support group and then proceeds to describe the dynamics of a suport group. Definitions proposed by several authors are discussed. The role and function of the facilitator at each stage in the life of the support group are presented. Tables are included listing facilitator behaviors for each of the developmental stages of the support group (pregroup, preaffiliation or inclusion, power and control, intimacy, differentiation, and termination). Ways of gaining experience before facilitating a support group are suggested. The need to acquire an academic knowledge base regarding the operation of support systems and of support groups, the need to observe and belong to an organized support group, and the need to allow the beginning facilitator to develop a small scale support group or to co-facilitate a support group are discussed. Emphasis is placed on the facilitator drawing out the expertise of the group members. (Author/NB)