The Committee on Allergen Standardization sent questionnaires to all members of the AAAI and ACAI requesting information regarding fatalities associated with skin testing or immunotherapy for the years 1985 to 1989. Information was collected on 17 fatalities associated with immunotherapy. No fatalities associated with skin testing were reported. The ages ranged from 12 to 77 years with a mean of 36.0 years. Eleven were female and five male. Thirteen (76.5%) had asthma. Sensitivity by skin test or RAST was judged to be high in 12. Fifteen were receiving pollen extracts (12 weed including ragweed and 9 grass). Four had had previous systemic reactions. Four were on maintenance and 11 on build-up injections. Four occurred when changing to a new vial. Two reported dosing errors. Eight received their injections in offices other than that of the prescribing allergist. Onset of symptoms occurred within 20 minutes in ten, 20 to 30 minutes in one, and greater than 20 minutes in one. Cause of death was associated with respiratory compromise in eleven. Overall risk of immunotherapy was low; however, several factors appeared to be associated with increased risk; unstable asthma seemed to be at greatest risk. Other factors that appeared to be associated with greater risk were high sensitivity, use of pollen extracts, and prior systemic reactions. The results suggest that special precautions, including a 30 minute waiting period, should be utilized for patients with moderate or severe asthma. Immunotherapy should be administered under the guidance of trained physicians aware of the risks and skilled in treatment of anaphylaxis, with proper personnel and equipment available. Patients should be fully informed before starting treatment, and screened before each injection to assess clinical status.