A pulmonary survey was undertaken in a large granary in the West of Scotland. The lung functions and respiratory symptoms were compared in nineteen atopic and fifty-six non-atopic grain handlers with reference to their smoking habits and also to forty-eight control subjects with no previous exposure to grain dust. Cigarette smokers from the granary workers and the control group had more respiratory symptoms and significantly lower PF, FEV1, V25 and V50. The atopic grain handlers, on the other hand, had better ventilatory functions compared to non-atopic workers. This difference in the atopic group may be related to their lower cigarette consumption, shorter service in the granary or the process of self selection. The grain handlers with wheeze or breathlessness at work had significantly higher incidence of restrictive type MEFV curves and this could not be attributed to increased cigarette consumption, atopy or longer duration of employment and there was no correlation between severity of symptoms and occupational exposure. Although PF, FEV1, FVC, V25, V50 and V75failed to show significant differences in granary workers and controls, the shape of MEFV curve may have significance as a sensitive indicator of the effect of grain dust as a preclinical stage.