The aim of the study was to examine the long-term changes in inhalation exposure to flour dust in the UK. Flour dust data held in the UK National Exposure DataBase (NEDB) and from one large company from 1985 to 2003 were reviewed. Analysis of the log-transformed data was carried out using linear mixed effect models and expressed as the relative annual change in exposure. 1451 inhalable flour dust measurements were analysed. The overall mean flour dust levels ranged from 7.8 mg m(-3) in the bakeries to 17.9 mg m(-3) in the flour mills. Analysis of the data obtained from NEDB and industry revealed no statistically significant temporal trends in exposure. Considering these high levels have persisted over the last 20 years, there is a need for government and industry to implement further measures aimed at reducing flour dust exposures and the risk of developing occupational asthma.