For many years there has been much argument whether workers in the dusty trades are prone to chronic bronchitis. In 1966 the Medical Research Council issued a report of a Select Committee which concluded that occupationally induced bronchitis did not play a significant part in the aetiology of airways obstruction in dust-exposed men. Since then epidemiological studies have demonstrated that the prolonged inhalation of dust leads to an increase in prevalence of cough and sputum. Furthermore, new physiological techniques have demonstrated a slight decrement in ventilatory capacity as a result of industrial bronchitis, and which is related to lifetime dust exposure. Unlike bronchitis induced by cigarette smoke, the predominant effect of industrial bronchitis is on large rather than small airways and the condition is not accompanied by emphysema.