The Clinical Investigation Unit has served as a natural focus for clinical research; as such it has a number of advantages and specific problems. On such units a variety of themes may occur. Some of these have the potential to interfere with the integration of clinical and research work. These include the theme that the research itself is therapy, or that research will find all the answers. Both may result in problems for the functioning of the ward. Most problematic of all is the theme that research is harmful and exploitative. Optimally, the unit develops an attitude that the research is compatible with excellent patient care. Problems of patients, staff, ethical issues, admissions policies and problems of the clinician-scientists are reviewed with recommendations on how to minimize difficulties.