We evaluated various patient characteristics in patients hospitalized for asthma during 1987 to 1990. Potentially fatal asthma was identified in 26 of 87 adult patients (29.9 percent) hospitalized. Patients with PFA had increased frequency of prednisone use prior to hospitalization (p less than 0.001), shorter duration of symptoms before hospitalization (p less than 0.001), longer hospitalization (p less than 0.001), were more likely to have had three or more prior hospitalizations (p less than 0.001), and had reduced presenting peak expiratory flow rates (p less than 0.05). Major psychiatric diagnoses and noncompliance were significantly related to PFA cases. The diagnosis of PFA identifies a higher risk patient with asthma. The data suggest that at the time of hospitalization the PFA patient has had a shorter recognized prodrome of increased respiratory symptoms, reduced peak expiratory flow rates and greater likelihood of major psychiatric disease or noncompliance. Effective ambulatory control of PFA and non-PFA is advisable with earlier use and higher dosages of oral corticosteroids.