Nurses administering aerosolized pentamidine (AP) were studied to determine any effect AP may be having on their health. Exposure was determined by each nurse's self-report of treatment given as recorded in a daily log and personal and area pentamidine sampling. Outcome measures were self-reported symptoms recorded in a daily log and peak expiratory flow rates (PEFR) and cross-shift and cross-week pulmonary function tests (PFTs). Results revealed no dose-response effect of pentamidine exposure on cross-shift and cross-week PFTs. However, declines in cross-shift PEFRs, diffusion capacities, and increased symptom complaints were observed for a subset of the study population. This suggested that outcomes were modulated by host factors (history of hay fever and allergy) as well as exposure doses. Treatment both efficacy in containing fugitive AP aerosol was also corroborated as a means of minimizing worker exposure.