We anesthetized five patients receiving antiasthmatics with sevoflurane-nitrous oxide-oxygen. Induction with sevoflurane inhalation was conducted uneventfully in all patients. Mild asthmatic attacks occurred in three patients during light anesthesia. The asthmatic attacks subsided with elevating the concentration of sevoflurane or the administration of aminophylline in two patients. In only one patient, inhalation therapy with salbutamol was required to treat an asthmatic attack during deep anesthesia. The results indicate that sevoflurane was a proper inhalation anesthetic for our asthmatic patients.