In order to evaluate peripheral and nasal eosinophilia and serum total IgE levels in ascariasis, 30 children between two and 12 years of age whose fecal samples were found to contain Ascaris lumbricoides, and 30 children between 1.5 and 12 years of age who did not have ascaris in their fecal samples, were enrolled in the study. Peripheral eosinophil counts and serum total IgE levels were significantly higher in the study group, but there was no significant difference between the nasal eosinophil counts of the two groups. Since total serum IgE levels differ according to age, the patients and the control groups were also evaluated within three age-groups. Peripheral eosinophil counts and serum total IgE levels of patients with ascariasis in all age ranges were significantly higher, but nasal eosinophil values did not differ significantly. These results show that in ascariasis the presence of peripheral eosinophilia and high total serum IgE levels are similar to those in atopic diseases, and some allergic symptoms such as nasal itching can be caused by parasites. However, nasal itching does not correlate with nasal eosinophilia in ascariasis. This is an important feature in the differential diagnosis.