Abstract: RFID-based system for tracking billable anesthesiology time in a surgical environment employs hand-held RFID reader devices that record and store timed anesthesia events for each surgical patient. Each patient is assigned a reader device, uploaded with patient data. Each anesthesiology professional has an identifying RFID transponder, and room transponders are located on wall or doorway of each room in the surgical suite. A download cradle is used for downloading the patient data collected during surgery to a central computer. The reader devices are synchronized to a high-accuracy clock, eliminating time accounting problems associated with concurrency and discontinuous time.