We want to define what we understand as a conflict of interests and its influence upon the relationship doctor-patient when ill managed. We offer antecedents that allow us to infer that the fundamental conflict in the clinical relationship is the so called "doctor's double agency". Bibliography on the subject has increased as a consequence of the system known in the United States as "Managed Care". This expression is very precise because its two words imply the two fundamental definitions of a clinician: on one hand, his obligation to "care" and, therefore, to do his best for his patient; on the other hand, his condition of "manager", that is to say, the manager of resources and his need to look over the financial control. This is the subject of the so called "doctor's double agency". This new scenery will change the future of the medical profession and we think doctors have an undeniable responsibility. We are at the verge of a paradigmatic change in medical practice which will also m