In the context of occupational health, spirometric testing of respiratory function has a number of important applications. These applications can be expected to become more widespread in view of extensive changes to occupational health and compensation legislation in South Africa. Spirometry is an essential component of pre-assignment medical examinations at the commencement of employment; of medical surveillance of workers exposed to hazardous substances so as to intervene when early changes in pulmonary function are detected; of medical evaluation of functional impairment for appropriate job relocation or compensation; and of research. These applications of spirometry each have special considerations which are detailed.