Awad OGAN - In adult individuals with recurrent tonsillitis, the researcher conducted this prospective cross-sectional study to examine the prevalence and contribution of humoral immunodeficiency. This research carried out over 3 years duration with two groups of individuals. Group 1: involved 50 normal adult individuals and group 2: included 50 adult patients with recurrent tonsillitis. Recruitment took place in a tertiary care hospital in Egypt. Compared with individuals with normal immunity, those with humoral immunodeficiency had a significantly higher incidence of tonsillitis and rhinosinusitis attacks. Such findings suggest that the assessment of immune function in these patients should be carried out regularly.