Some of the complex aspects of the role of the liaison psychiatrist as illustrated on a renal dialysis service have been discussed. The liaison psychiatrist is expected not only to fulfill the role of a medical consultant but also to facilitate communication amongst staff and to participate in decisions of life and death. The diversity of these tasks may contribute to the ambiguous identity of the liaison psychiatrist but has also provided fertile ground for research and clinical practice. The important functions of other non-psychiatric staff, including the social workers, have been referred to but not discussed at length here.