The ability to accurately obtain and interpret spirometry is essential for physicians caring for patients with asthma and inflammatory disease of the airway. This article reviews the basic equipment, setting, and personnel needed to obtain quality spirometric data. The fundamental measurements obtained in routine office spirometry and recommendations that are critical to obtaining high-quality reproducible test results are reviewed. The evaluation of flow-volume loops and normative data is discusses as well as criteria that define a quality measurement. Examples of normal spirometric data as well as data from different disease states are reviewed.