The medical reasons for rejection among 3,000 consecutive applicants for flight training were evaluated, and the effectiveness of the screening process determined by reviewing subsequent medical wastage occurring during flight training. Of the 46 cadets who left the course because of medical reasons, 8 withheld information which would have led to their rejection on the original screening examination (epilepsy 1, recurrent syncope 1, migraine headache 2, Crohn's disease 1, asthma 1, chronic knee pain 1, and chronic recurrent headaches 1). There were also two errors in medical processing. The other 36 cases could not have been predicted by current screening procedures. We conclude that the major deficiency in our screening process is the concealment or withholding of information by candidates for flight training.