Adenoid hypertrophy is one of the reasons of otitis media with effusion. The aim of this study was to inquire whether it has got an influence on the number and activity of peripheral blood T and NK cells. The examined group consisted of 119 children with adenoid hypertrophy. The first group consisted of 44 children with only one episode of otitis media with effusion (OME). The second group consisted of 45 children with more than 4 episodes of OME and the third group consisted of 30 children with adenoid hypertrophy without OME. Evaluation of percentage of CD4+, CD8+ and NK subsets with co-expression of CD69, HLA-DR molecules in peripheral blood was performed by flow cytometry method. In examined groups with OME the decrease of CD4 number was compensated by increase of the number of NK and CD19 cells. In these groups the increase of CD69 and HLA-DR expression on the examined subsets was observed. The results suggest that recurrent otitis media with effusion may be one of the factors causing T lymphocytes deficiency. Obtained results might be one of the criteria of using adenoidectomy.