The health screening methods have been suffering considerable modifications through the years. The introduction of the digital electronic computer and the clinical laboratory automation allowed us to reach a process known as "Multiphasic and Automatic Health Screening". "Multiphasic" because of the fact that various tests can be done (spirometry, E. C. G., audiometry, laboratory tests, etc.) and "Automatic" because of the utilization of the computer, the Auto-Analyzer and other similar equipments. The results of the various tests can be evaluated by the computer in two ways: "on-line", when various equipments are directly connected to the processing unit, "off-line" when the results are preliminarily registered in a punch card, mark sense page etc. The two tecniques are described and exemplified with the University of São Paulo experience (off-line method), and that of a private organization (on-line method), and the importance of that methodology in Preventive Medicine is emphasized.