The introduction of clinical supervision in nursing is gaining momentum and is proposed as having numerous benefits for nurses, organizations, and ultimately patient care. The necessity for such supervision has arisen partly from a fundamental shift in the nature and definition of nursing work. The emphasis on individualized, holistic care has led to a change in role from one characterized by professional distance to one in which interpersonal involvement is seen as central. Such a shift, though seen as positive, may lead to increased vulnerability as nurses negotiate the blurred boundaries between the personal and the professional in their relationships with patients. Such boundary negotiation is a legitimate focus for learning and support in clinical supervision. However, as with many aspects of nursing, the subtle processes involved in relationship development are often hidden from consciousness, thus missing potential learning opportunities. One way that such hidden aspects of practice may be explored in clinical supervision is through attendance to the way that such processes are parallelled in the supervisory relationship. Drawing on theory and practice from the fields of counselling and mental health nursing, this paper explores the nature of 'parallelling' in clinical supervision. The implications for clinical supervision in nursing more generally are examined in relation to enhancing learning and providing support for supervisees and supervisors.