Computer-based monitoring of the workplace is a fairly recent phenomenon about which little is known. This study investigates how computer-based monitoring is currently operating and how it affects the work process and the quality of work life for employees. The study also focusses on the economic justification for computer-based monitoring. The research is conducted as a multi-site case study of four firms in Tucson, Arizona that use computer-based monitoring. Data is collected through observation, structured interviews, and questionnaires over the course of one year.