IgG subclass levels were studied in 12 children, aged between 2.5-12 years with recurrent respiratory tract infections. They did not have low IgG levels or IgA deficiency. We found combined deficiency of IgG2-IgG4 in one patient and selective IgG2 deficiency in another (16.6% of patients). These two patients had bronchiectasis due to recurrent severe pneumonia, however one patient with bronchiectasis had normal IgG subclass concentrations. Our IgG subclass-deficient patients who did not respond to prophylactic antibiotic therapy were given gammaglobulin therapy. IgG subclass deficiency should be considered in children with unexplained recurrent infections even in the presence of normal serum immunoglobulin levels.