During the 1980's, three national surveys of oral health status were conducted by NIDR on school children and adults. Measurement criteria for these surveys were defined, tested and refined to have them be as specific as possible. This aided in calibration of examiners so that measurements were as reproducible as possible. Illustrations of the various dental/oral conditions were solicited from a wide range of sources for each dental/oral condition. Examples were selected that best demonstrated a specific condition or that could be used as teaching aids for decision making. Definitions and full-color illustrations for the following indices used for the surveys--coronal and root caries, enamel fluorosis, periodontal assessment including gingivitis, calculus and attachment level as well as oral soft tissue lesions commonly found in children-- were assembled in a spiral bound publication. This manual is designed as a training or teaching aid for oral health measurements, particularly for researchers and others planning surveys of oral health status. Chapters on data collection procedures, materials and equipment used in the national surveys conducted by NIDR are also included. NIH Publication No. 91-2870, Jan. 1991, Oral Health Surveys of the National Institute of Dental Research - Diagnostic Criteria and Procedures is available for dental epidemiologists and others involved in large-scale oral health assessments.