A disorganized attachment pattern is found among several mental disorders, most notably among severe personality disorders (PD). It is characterized by profound mentalizing deficits, which makes relations to self and others highly problematic. There is no evidence of any preferred mode of psychotherapy to heal this condition. In this article we describe the successful treatment of a female (28) with schizotypal and avoidant PD with additional borderline features as well as substance use dependency. She participated in the mentalization-based treatment project of the Bergen Clinic Foundation, Norway. We discuss the therapeutic strategies and interventions that most probably mediated the change for this patient, highlighting the mentalizing stance, working in the transference, managing countertransference and repairing alliance ruptures.