Constantly there is a necessity for carrying out tests on hardened concrete to determine the parameters of concrete strength in structure. Nowadays for concrete control quality testing nondestructive test methods are widely used. For this purpose mostly used methods are ultrasonic pulse velocity and rebound hardness by applying portable devices ultrasonic tester and Schmidt rebound hammer. Although, many such tests have been carried out, they all still lead to difficulties in interpretation of the results, because they are affected by a number of factors. During the inspections of different building objects, comprehensive information on technical condition of concrete and reinforced concrete constructions have collected, simultaneously applying the nondestructive test methods and testing specimens taken from constructions of buildings until failure. It has been defined some novelties by working with two aforesaid nondestructive test methods in conformity with determination of concrete actual strength. And namely, there are comparing dispersions of the measurement data by ultrasonic tester and Schmidt rebound hammer. Besides, compli-ance of the groups of measurement data for these testing methods to the normal distribution nature is to be related. Simultaneously it is established also how the amount of measurements affected to correlation relations between re-sults of the concrete nondestructive test methods and the strength destructive testing data. Finally, obtained test re-sults are compared to the interpretation of measuring data for concrete strength theoretical calculation by other scien-tists from countries outside the Europe