The role of epidemiologic surveillance in detecting and controlling occupational asthma was discussed. The importance of initial investigations of sentinel cases of asthma by cross sectional, census sample evaluations was stressed. Questionnaires were considered essential components of the survey, serving the same function as the medical history in a clinical examination. Several methodological issues arising from questionnaire use were discussed including validity, especially in the absence of a true gold standard for asthma, and reliability. Physiologic assessment of occupational asthma was discussed including pulmonary function tests with and without bronchodilator treatment, spirometry before and after work shifts, ambulatory monitoring of peak expiratory flow rates over several weeks, and bronchial provocation with nonspecific agents such as histamine or methacholine. Environmental assessment was considered as a response to worker complaints, evaluation of worker exposures and engineering controls, and determination of workplace compliance to standards. Numerous specific recommendations were made to ensure the integrity, validity, and reliability of the initial evaluation design, questionnaire instruments, pulmonary function evaluations, and environmental monitoring procedures.