The trend in asthma mortality in Hong Kong was estimated from published statistics for the years 1976-85. To avoid coding errors in death certifications, only asthma deaths in the age group 5-34 years were analysed. Mortality rose annually by an average of 10.5% in male (P less than 0.02), but not female asthmatics. Such an increase was not due to a change in coding as a result of the revision of the International Classification of Diseases in 1979, or an exchange of diagnostic labelling from other respiratory diseases. The exact causes for the increase in asthma mortality have yet to be determined.