This study examines the relationship between the therapist's own attachment representation (Adult Attachment Interview, AAI) and the patient's attachment relationship to the therapist (client's attachment to the therapist, CATS). The attachment representations of n=22 psychotherapists who treated n=429 patients were assessed. A general effect of the secure/insecure therapist attachment status on the attachment of the patient to the therapist was not found whereas the more specific effects expected could be confirmed: The more preoccupied the therapist's attachment status was, the more the patient experienced a preoccupied-merger attachment to the therapist. The more dismissing the therapist's attachment status was, the more the patient experienced an avoidant-fearful attachment to the therapist. In summary, not the general security/insecurity of the therapist's attachment representation but rather the type of the insecurity is associated with the subjective patient's attachment-related experience of the therapeutic dyad.