: Spirometry in the occupational health setting plays a critical role in the primary, secondary, and tertiary prevention of workplace-related lung disease. Recognizing the central role of spirometry in workplace respiratory programs, the American College of Occupational and Environmental Medicine (ACOEM) developed three spirometry position statements in the past two decades, which summarized advances of particular relevance to occupational health practice. However, since these statements were published, there have been important developments in federal regulations and in official American Thoracic Society recommendations which affect occupational spirometry testing. This 2020 ACOEM guidance statement incorporates these spirometry testing changes into its recommendations to provide current information for all users of spirometry test results, from those who perform or supervise testing to those who only interpret or review results.