Inter group supervisory model in respect of medical activities is based on concentrating and using the expertise of medical and health professionals related to supervisory duties. This makes the authorities and personal in medical institutions aware that they are supervised by professional supervisors when dealing with the patients. This ultimately makes personnel avoid making some problems and neglecting their duties. On the other hand, applying such a model has some disadvantages. Using extra- group model is based on the principle of separating the supervisor from the decision-maker and the autonomy of the supervising board in respect of the medical departments in order to avoid prejudice in supervising. Dividing this model into the institution-based and the process-based mechanisms is achieved to guarantee performing the duties of hospitals, therapeutic and medical centers. In general, studying such models will give us an exact knowledge of supervision process. Reaching a conclusion-based process is important to select a model in order to apply an organized supervision in the systems of Iranian hospitals.