Abstract : For the past several years, RADC has been developing technology for use in future entry control systems. This research and development has been done in support of the Defense Nuclear Agency and the Physical Security System Directorate (formerly the BISS SPO). The main thrust of this R&D has been in the development of highly reliable, automated methods of personnel identity verification. The technology that has emerged has been based on personal attributes such as speech, fingerprint, and handwriting to form the basis for highly accurate Personnel Identification and Authorization (PIA) techniques. Laboratory and field tests performed by RADC and other Government and private organizations have clearly underscored the need for the application of behavioral science and human factors engineering in the design, development, and testing of entry control systems. The purpose of this paper is to discuss some of the major human factors aspects associated with military entry control systems. This discussion will focus on the man-machine interaction between security guards, users, and imposters with entry control systems. It is these interactions which can strongly influence the overall security of an entry control system, the acceptability of the system to users, and the likelihood of penetration attempts. (Author)