AL-Yousif, Mohammed Abdulaziz2022-05-182022-05-1820041714https://drepo.sdl.edu.sa/handle/20.500.14154/3631This research represents a field study to find out the level of application of quality systems have had 30 contractors 0.5 Twenty-five of concrete contractors who are classified with the Ministry of Public Works and Housing 0.5 Five of the non-classified in the Eastern Province in Saudi Arabia The study showed that contractors are generally classified matter to a higher level in quality control applications of non-classifiedenThesis