To investigate the asthma mortality rate in Sweden for the period 1973-88, we reviewed all death certificates for suspected death from asthma coded as 493 of the International Classification of Diseases (ICD)-8 and ICD-9 for the age group 1-24 years. Age-related mortality rates were calculated and compared with the results from a previous Swedish study of 1952-72. To identify factors contributing to death, we assessed hospital records. The mortality rate was 3.46 for the period 1973-88 and 3.31 for the earlier period, a net increase of 5%. This small overall increase includes a minor decrease in deaths for the age group 1-14 years and a rather pronounced increase for 15-24-year-old asthmatic patients. More deaths among "mild" asthmatic patients were found in the higher age group for 1986-8 than 1973-81. In younger children, asthma was more severe, and no difference was found between the two periods of the study. Asthma mortality is increasing in Sweden in adolescents and young adults, and there is a tendency to increasing mortality from less severe asthma not treated with anti-inflammatory drugs.