In spite of increased asthma prevalence, the mortality in the disease has decreased during the last two decades in Sweden and in some other countries. However, in the age group 15-24 years an increased death rate was noted at the end of the 1980s. Therefore we started a prospective study from 1994 with the aim of trying to analyse the precipitating factors of all deaths in the ages 1-34 years in which the death certificate alleged asthma or anaphylaxis as the main or contributing cause of death. We conducted a confidential telephone enquiry of the next of kin of the deceased using a modified questionnaire developed by the British Thoracic Association. When available, patient records and post mortem protocols were obtained. RESULTS: The mortality in asthma in the ages 1-34 years has decreased from around 5 per million/year to 0.5/million/year over the period 1987-1998. The main preventable factors found in this analysis are undertreatment, non-compliance, psychosocial factors including alcohol/drug abuse, food allergy and inhalation allergy. Lacking awareness of the risks and underestimation of the severity of the asthma both by the physician and the patient seem to be dominating factors.