There is rich theoretical literature that cites the importance of the therapist’s use of self as a way of knowing, especially in cases where a patient has been severely traumatized in early life. There is limited empirical research that explores the in-session experience of therapists working with traumatized patients in order to support these claims. This study employed a qualitative design to explore a therapist’s internal experience when a patient dissociates in session. The aim of this study was to further develop the theoretical construct of dissociative attunement to explain the way that therapist and patient engage in a nonverbal process of synchronicity that has the potential to communicate dissociated images, affect or somatosensory experiences by way of the therapist’s internal experience. Findings revealed that therapists have strong emotional and behavioral responses to a patient’s dissociation in session, which include anxiety, feelings of aloneness, retreat into one’s own subjectivity and alternating patterns of hyperarousal and mutual dissociation. Findings also revealed that the process of dissociative attunement is at play when a patient dissociates in session. The process of dissociative attunement was comprised of seven component parts: Disjunction and Connection, Perception of Nonverbal Cues, Induced Feeling, Therapist as Placeholder, Asymmetry of Roles and Responsibility in the Dyad, Containment, and Therapist Imaginings. Findings imply that a patient’s dissociation in session should be considered an interpersonal phenomenon that holds the potential to communicate important aspects of the patient’s affective experience and needs through examination of the therapist’s internal experiences.