A seroepidemiologic study on American trypanosomiasis was performed to a group of Nicaraguan students in Isle of the Youth Special Municipality, during February 1987, using indirect hemagglutination and indirect immunoflorescence techniques. The prevalence obtained with both tests and the percentage of the most frequent titer of indirect immunofluorescence are pointed out. The youth living in rural zones presented higher risk of acquiring the infection than those living in urban zones. The students coming from the Atlantic Coast, Rio San Juan and Masaya, presented the highest positive rates. Of those who were interviewed, 59% identified the Triatoma, and 13% of them manifested to have seen it inside homes. The background of being bitten by the Tritoma was present in 16.2% of those with positive results.