For the identification of microfilariae in buffaloes, seventy one blood samples were collected from a total of 10 local flocks located at different parts of Nineveh governorate /Iraq. Blood samples were tested with Modified Knott's technique. Results showed (100%) infectivity for all examined samples and belongs to genus Seteria. Detected microfilaria was sheathed with rounded front end and pointed posterior one with the lengths ranging from 200-625 µm. The number/intensity of Microfilaria infection of all examined Nineveh districts were as follows,  Al-Quba (93/28.7%) with a mean length of 375 μ ,  Al-Shalalate (60/18.5%) with a mean length of  417 μ,  Al-Rahmania  (57/17.6 %) with a mean length of 383 μ,  Badush flocks (A, B and C) and were  (24 /7.4%), (8 /2.5%), and (46 /14.2 %) with mean lengths of  435, 375 and 427 μ respectively , Bab Shams (14/ 4.3%) with a mean length of 443 μ, Al-Slamia  (10 /3.1%) with a mean length of 370 μ, and with the same number and intensity both Hawy Al-Kanisa and Mafraq Telkief  (6 /1.9%) with a mean length of 388 and 442 μ respectively. For identification the possible carriers of microfilaria , different flies in the same buffaloes barns were collected, and four species of flies were reviled: Musca domestica, Luciliasericata, Tabanusspp and Simulium spp < /em>. The importance of  Microfilariae and the role of black flies as a vector were discussed.