This study was conducted during June 2016 to May 2017, to determine the morphological characteristics of stable fly Stomoxys calcitrans L. ,and studying some ecological aspects. These studies of stable flies are being conducted for the first time in Iraq.The morphological diagnosis of Stomoxys calcitrans: Frontal vitta with black pollinose, yellow around ocellar triangle, parafrontalia golden, parafacialia grayish black. Thorax gray to yellowish pollinose, Pleura yellow; sternites dark brown to black, Legs black, Wing tinged smoky-brown. Abdomen gray to yellowish; dorsum with four brownish pollinose spots, at least 3 abdominal segments with a single median spot basally and pair of spots at apex of each segment. Female identical to male in color and structure