Abstract: A simple and sensitive immunoenzymatic assay-ABC(Avidin-Biotin-HRP Complex). ELISA for detection of anti-hydatid specific IgE antibodies is presented. Sera from 40 patients with hydatidosis tested by both ABC-ELISA and conventional ELISA showed that the former was more sensitive than tne latter, particularly in cases with IgE in lower levels. The positive percentages were 92.5% and 82.5% in s閞um samples diluted 1:100; 75% and 57.5% in 1:200, respectively. The difference of non-specific reactions in 24 cases with cysticercosis cellulosae and 25 cases with allergy was not significant with the two methods. The average levels of total IgE tested by the ABC-ELISA in patients with hydatidosis, cysticercosis, or allergy and in 25 healthy blood donors were of 5 982.96, 3 449.88, l 334.43 and l 150.54 IU/ml respectively, and the deviation from mean square showed differences of statistical significance.