A system for recording information on patients and contacts was developed during a research project designed to measure the effectiveness of contact tracing. The record system has proved valuable in contact tracing, cross-referencing patients and their contacts, defining the characteristics of the patient and contact populations, and providing information for research and management. The value of a standardized system was accepted by health workers who appreciate that its purpose is to increase efficiency and improve the care of infected persons. By Oct. 1976 health workers in 16 clinics in the United Kingdom started to use the system. [This study had relevance to gonorrhea and syphilis epidemiology.].