Clinical evolution of 94 diagnosticated children of bronchial asthma that received hyposensitization therapy for 18 months and other 43 children in treatment for 24 months is studied. Their sex, etiology, age of onset of their illness and age in which their treatment began are analysed too. A long delay is noticed between the onset of the asthmatic crisis and the moment in which they are taken to the Allergy-Clinic. CONCLUSIONS a) Hyposensitization therapy supposes a significative statistical clinical improvement, leading in most cases to keep under control the illness with a vanishing of symptomatology. b) The improvement does not depend upon sex or the age of onset of the illness, although it has some relation to the time of evolution. c) Clinical improvement may be delayed even 24 months later after the beginning of treatment.