Assistance dogs have long been used to help with physical disabilities and are now increasingly being used by patients suffering from a host of psychological ailments. As assistance dogs enter the physical space of the psychotherapist's office, we should consider their effect on the psychological space. Psychoanalytic theory and technique have evolved to address the ways that the participants’ subjectivity may influence each other. The presence of an assistance dog in the consulting room inevitably contributes to the treatment process, especially affecting the subjective experience of both patient and therapist. In this paper, a clinical example is used to describe the intersubjective experience of the therapist, the patient and the assistance dog.