The incidence and prevalence of occupational asthma has been extensively studied in industry settings and specialist clinics. However, it has been much less studied in the community. This study looked at the general practice notes of asthmatics in an attempt to assess the overall load of occupational asthma in the community. Eighty-six per cent of the patients with adult onset asthma in the practice population studied had at least one occupation recorded in their notes. Nearly a third of these (32%) were in jobs known to be significant causes of occupational asthma, yet a potential link between their occupation and symptoms had only been recorded in 18% of patients in these jobs. Overall 4% of the patients with adult onset asthma had been given a diagnosis of occupational asthma although in nearly half these cases the diagnosis had been made by a general practitioner and not a specialist.