A computerized tracking system for both preventive care and chronic disease tracking was implemented at a community health center, using a PC based local area network interfaced with a mainframe scheduling and billing system. Initial database construction used downloads of historical billing data, but ongoing database maintenance is accomplished by using an optical mark-sense scanner to construct both billing and clinical tracking files from custom-designed encounter forms. In this way, expanded clinical data is collected with an actual reduction in manually keyed data, reducing the ongoing cost of the system.