One hundred cases were suffering from chronic tonsillitis, aged between 4-12 years, of both sexes (60 boys and 40 girls), from. outpatient clinic of E.N.T. unit at Benha Faculty of Medicine• They were examined serologically by indirect haemagglutination — antibody technique (IHAT) for toxoplasmosis. After tonsillectomy, histopatho... logical and electronmicroscopical studies were done. Ten percent of cases were positive serologically, among boys (11.71%) and girls (7.5%). The positivity rate was high among age group 10- 12 years than others. Two cases showed histopathological and ultrastructural changes indicating toxoplasmosis. INTRODUCTION Lymphadenopathy is considered the most common finding in acquired toxoplasmosis (Rifaat et a!., 1977). The cervical, posterior auricular and occipital lymph nodes are usually affected and to less extend is the inguinal and axillary nodes (Jones et al., 1965). The tonsillar tissues, as bieng a part of the lymphoid tissue, were postulated to be a site of Toxoplasma infection (Kouba et al., 1977 and Palick and Cihak, 1977), Rifaat et al. (1977) did an important serological study of toxoplasmosis patients with chronic tonsillitis and re