Spirometry plays an important role in occupational respiratory health surveillance programs. However, when not performed correctly, the values obtained can be misleading, resulting in misclassification of the workers' health status. Studies carried out in Italy have shown that spirometries recorded by occupational physicians often do not comply with quality criteria for recording FEV1 and FVC, according to joint statements on lung function testing for the American Thoracic Society and the European Respiratory Society, issued in 2005. For this reason, they are useless for the purposes of their execution. Compliance with ATS/ERS statements is essential to assure that spirometry results are beneficial for the monitoring of workers' health.