Spirometry is a basic pulmonary function test that is widely used for the detection of airflow limitation. Its use will continue to grow in the medical office setting because it is useful for both diagnostic and monitoring purposes. Additionally, the assessment of airflow reversibility is a quick, safe, and useful adjunct to baseline spirometry. Many manufacturers offer various models and types of spirometers. Before purchasing, determine the needs and characteristics of the office and its staff, and then choose an appropriate device. There is no "holy grail" for selecting what instrument is best for a specific office. Rather, it requires time and effort to make a good choice. Carefully assess the instrument before purchase and, ideally, compare several instruments. Once an instrument is purchased and it arrives, carefully validate it before reporting results. Proper training of the technicians who perform the testing is perhaps the most important factor in obtaining good spirometric testing. After adequate training, it is also important to have continued competency assessments, periodic inservices, and careful review of test results. The ATS and American Association for Respiratory Care (AARC) published extensive guidelines on the performance of spirometry. These recommendations should be followed to ensure quality and reduce interlaboratory variability. Patients should be properly prepared, the instrumentation properly calibrated, and the test conducted so that there is a good start, adequate exhalation time, satisfactory end-of-test, and good reproducibility between trials.