Since the Veterans Administration (VA) authorized compensation and other benefits for posttraumatic stress disorder, delayed type, in October 1980, the agency has received an increasingly large number of claims--mainly from Viet Nam veterans--for this disorder. An unprecedented challenge of the adequacy of psychiatric disability evaluation in the VA has thus been created. The authors describe efforts in one large program to meet this challenge and review 12 problems in the diagnostic process. Cooperation of all parties in claims transactions, thorough claimant assessment, reliance on DSM-III criteria and methods and consultation with examiners are essential principles for this work.