One of the most important factors that directly affects the quality of health care is patient safety. Minimize the occurrence of adverse events is one of the main challenges for health professionals. This requires continuous tracking of the patient by different areas and services, a process known as traceability and proper patient identification and medication prescribed. This article presents an information system for patient tracking and drugs developed for the Emergency Department of Hospital A Coruña. The systems use RFID technology to perform various tasks: (1) locate patients in different areas; (2) measure patient care times and waiting times; (3) identify unitary doses of medication; and (4) ensure the correct matching between the patient and the medication prescribed by the doctor. The hardware infrastructure as well as the optimal configuration of devices interconnected via a wireless network was determined by conducting a detailed coverage study. To support all the functionality needed, specific tools were designed and integrated with proprietary software applications. The RFID system was evaluated positively by staff from different professional profiles involved in its development or subsequent implementation.