Mortality due to asthma was recognised by Thomas Willis in 1671 though it was not until the early 1960s that an epidemic of death raised major concern in the United Kingdom. Initially over-treatment with beta agonist aerosols was blamed as the cause both here and in Australia and New Zealand. Further studies in London, Cardiff and Birmingham suggested this was not the case, rather that under diagnosis, under appreciation and under treatment were a more common cause of asthma mortality. The British Thoracic Society's confidential survey in 1979 confirmed these findings and further suggested that wrong certification was a potential source of inaccuracy in older age groups.More recently the New Zealand Asthma Task Force have reported the results of a two year national survey of deaths, revealing similar results to the UK studies, also finding little evidence of beta agonist over usage, little effect of nebulized drug administration and no significant theophylline drug over usage.An examination of trends in Asthma Mortality in the United Kingdom by Stewart and Nunn (9) shows that the changes in the World Health Organisation I.C.D. coding of 1967 and 1978 had little overall effect on asthma death certification in the 15–44 year old age group. When this is taken into account they found that asthma mortality has declined from 1958 to 1982 in females but that there has been no change in males despite therapeutic advances over the period. Asthma mortality date derived since; however, does suggest a small but significant annual incremental rise in the 15 to 44 year age group. A larger rise in the older age group could possibly be accounted for by a change in the certification habits of doctors resulting in a transference from the diagnosis "chronic bronchitis" to "asthma" though this remains to be demonstrated. This potentially important cause of inaccuracy of certification could influence asthma death reporting in any community.