Selected immunologic parameters and effectivity of immunotherapy was evaluated in 117 children (12-month-10-year-1-old) suffering from recurrent respiratory tract infections. All the children displayed a profound depression of T lymphocytes number, which resemble the situation seen in AIDS patients. An increase of serum IgM concentration was also noted. Immunotherapy included treatment with the following preparations: TFX and Levamisol which stimulate T cell functions, Broncho-Vaxom which stimulates specific antibody production and a complex herb preparation PADMA showing undefined general stimulatory activity. Separate group of children was subjected to climatotherapy in Czerniawa Sanatorium and received no immunostimulants. All methods of treatment employed had beneficial effect. The highest percentage of positive results was obtained in children receiving TFX and Levamisol. In all groups under study, an elevation of T cells percentage was observed. This was especially evident in Levamisol treated patients. There was no correlation, however, between T cells number and clinical improvement.