To minimize the possibility of errors, many tests have been developed that are performed with or without destruction of the material. Non-destructive testing (NDT testing) is of great importance because it is often not possible to perform destructive testing (eg on a finished product). The topic of this paper is one of the most commonly used NDT tests - radiographic examinations and ultrasonic examinations. In the introductory part, the importance of non-destructive testing in the technical profession is described. In the continuation of the paper, a historical overview of the development of individual non-destructive testing methods is given. Various scientific achievements have enabled the development of research as it is known today. The paper also contains a description of errors in the material that are detected by non-destructive testing, and the importance of professional training of staff to implement these methods, is emphasized. In the continuation of the paper, the most important non-destructive methods that are most often used in practice are briefly described, namely: visual method, magnetic method, penetrant method and thermographic method of material testing. The purpose of radiographic testing is described in detail below, as well as the principle of operation and what it is based on. Radiographic testing depend on the type of radiation used to obtain radiographs. The paper describes radioactive radiation: x-radiation and ɣ-radiation, which also influence the choice of the type of radiographic testing procedures. The main types of radiographic examinations are described, namely: radiography, gammagraphy and radioscopy. In addition to radiographic, the paper also describes in detail the non-destructive ultrasonic testing method: principles, specifics, equipment, as well as the method of displaying feedback obtained by ultrasound. The most important methods of ultrasound are also explained, namely: acoustic emission, resonance method and pulse - echo method. The last chapter is the experimental part. These test methods were analyzed in practice on the example of "TERMOENERGETSKA POSTROJENJA đ.đ."