This report describes the development of a new scale designed to establish how therapists intervene and clients respond during effective enactments in family therapy sessions. The Family Therapy Enactment Rating Scale (FTERS) was developed by clinically trained investigators who observed 27 videotaped family therapy sessions and listed therapist interventions and client responses during four phases of enactments: pre-enactment preparation, initiation, facilitation, and closing commentary. Interrater reliabilities for the FTERS were calculated by training 6 undergraduate volunteers to rate independently a sample of 12 enactments. When reliabilities were found to be relatively low, a second study was conducted in which the FTERS was revised and reliabilities were calculated with a different sample of 21 videotaped enactments and a new group of 6 undergraduate raters. Reliability for the FTERS was found to be sufficiently robust to make this measure of therapist interventions and client responses a useful instrument for evaluating what takes place during enactments. Findings on the FTERS were used to offer tentative guidelines for effective initiation and facilitation of enactments in family therapy sessions.