This study included diagnosis of microfilaria in sheep in different methods which it is Knott`s concentration techniques and staining by Giemsa stain and staining by acridine orange fluorochrome in blood sample in Nineveh in Iraq. we examined 150 sheep blood sample the percentage of infection by Knott`s concentration techniques is 64% and the result is comprised with the results of  acridine orange fluorochrome is about 83% while the percentage of infection by Giemsa staining method is about 43% and summary of what we have reached that staining with acridine orange fluorochrome is the more efficient than other methods in microfilarial detection, as well as this study is the first by using acridine orange fluorochrome in sheep blood sample in country.