The responses of children with perennial bronchial asthma to three conventional methods of hyposensitization therapy and to a saline control treatment have been compared. There were approximately 40 children in each treatment group. The measures of response utilized were incidence of new allergies during treatment, incidence of wheezing on exertion and with upper respiratory illness after 4 years of treatment, and numbers of asthma attacks and days wheezing during the fourth year of treatment relative to the numbers in the year preceding treatment. The conclusion was that hyposensitization therapy, using sufficiently high doses of the antigen mixture, is quite effective in controlling the symptoms indicated above.