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Nowadays, the use of polymer composite materials in various industries has been increased due to their good mechanical properties, lightness, sound and thermal insulation and corrosion resistance. Over the past two decades, carbon fiber reinforced polymer (CFRP) materials have been widely used in aerospace and automotive industries. These materials may be subjected to impact during manufacturing or service period and a lsmal impact region may be produced in them. This small defect can reduce the mechanical properties of the structure and lead to its failure. Therefore, it is necessary to use a method for defect detection in these materials. In this study, a polymer composite sample made of carbon fiber in polyester resin was made and subjected to impact test. To consider the repeatability of the defect detection process, the sample was subjected to four various impact tests and the defect areas were evaluated using penetrant-enhanced X-ray radiography and ultrasound immersion pulse-echo C-scan. The image obtained from the penetrant-enhanced X-ray method was scanned using a digital scanner, and the image of the ultrasound C-scan test was calibrated, taking into account the step of scanning.The areas of the defect region were obtained using Imagej software. The results show that these methods are able to detect and measure the impact area in the composite sample and Ultrasonic C-scan method detect impact area more accurately.