One of the main objectives during the detailed examination of the supporting structures made from any construction materials is receiving data to perform calculations. For reinforced concrete structures the most difficult task is to determine the parameters of steel reinforcement, as it is always under a protective layer of concrete. The paper deals with the main problem of reinforcement parameters determination of concrete structures in the inspection. The basic well-known tracks of a solution to this problem are analyzed. The most reliable and accurate methods of reinforcement parameters determination are revealed. The magnitude of error of the magnetic inspection method in the determination of the diameter of reinforcement and the coverage is experimentally detected. The availability data of applying the method of hardness measuring for the reinforcement class determination is adduced.