A system for tracking the position of one or more medical devices for insertion into the body of a patient is disclosed. The system may also be used to locate one or medical devices at a later time after placement thereof. The present system employs multiple radiating elements that can be simultaneously detected by a sensor unit of the system, wherein at least one of the radiating elements is included with the medical device. Another of the radiating elements may be placed at a predetermined point on the skin of the patient to serve as a landmark to help determine the location of the medical device with respect to the landmark. Detection of the radiating elements by the sensor unit enables the relative positions of the radiating elements to be ascertained and depicted on a display, to assist a clinician in accurately positioning the medical device, such as a catheter.