As part of a comprehensive review of clinical research tools used in adolescent psychiatric disorders, a survey of 200 recent studies of adolescent anxiety (publication dates of December 1994 to May 2001) identified 70 different diagnostic and symptom measurement instruments. The design features and psychometric properties of the 15 most commonly used instruments were reviewed, and their strengths and weaknesses were evaluated. The conclusions arising from this review are: (1) too many different instruments are being used by investigators; (2) more than 20% of studies did not report the use of developmentally appropriate (i.e., child/adolescent-specific) diagnostic instruments; (3) another 15% of these studies relied on diagnostic instruments that demonstrate substantial weaknesses in reliability and validity; (4) the concordance between anxiety disorder diagnoses from different interview schedules is unknown; (5) the relative validity of diagnoses and ratings of anxiety severity based on information yielded by parents versus information yielded by adolescents is unclear; (6) clinician-rated symptom severity scales specific to anxiety disorder are rarely utilized; (7) the most commonly used self-report measures discriminate poorly between anxiety and depression, and their items are not indexed to specific anxiety disorders; and (8) some newer self-report anxiety instruments discriminate well between anxiety and depression and have diagnostic validity for specific anxiety disorders.