A kinetoplast DNA hybridization probe method was used to detect Leishmania within sand flies and to distinguish it from the non-pathogenic flagellate, Endotrypanum. Eighty-one sand flies (74 Lutzomyia umbratilis, 1 Lu. anduzei, and 6 Lu. shannoni) collected outside Manaus, Brazil were dissected. Forty-four of these were found to be infected with flagellates, and 2 hybridized with a Leishmania braziliensis probe. Thirty-three of sixty-one flies reprobed with an Endotrypanum probe were positive.