For two decades, the FAA Civil Aeromedical Institute ((CAMI) has explored the problems of effectively selecting air traffic control specialists (ATCSs) for the FAA. The results of those efforts have contributed directly to the establishment of revised ATCS selection standards by the Civil Service Commission (CSC). Early studies on the validity of aptitude tests for predicting successful completion of Academy training led to a decision to use such tests for part of the CSC screening standard. Later studies led to the establishment of a maximum age standard of 30 years for entry into ATCS training. In addition, CAMI researchers have continuously evaluated the validity of existing standards, have examined numerous variables and alternative aptitude measures, and have provided a number of data-based recommendations in an effort to improve predicting of success in ATCS training. This paper reviews that research with emphasis on aptitude screening measures, attrition, age, prior experience, education, sex, military ATCS training, and the Uniform Guidelines on Employee Selection.