The studies performed in present article are directed on improvement the practical methods of the existing steel structures examination. In particular, the new method for the determination of the mechanical properties of steel structure elements of the existing buildings and structures is offered. It consists in drilling a reference sample, made of structural steel, which have already been defined for mechanical properties of steel, and also the material of investigated structural element with the following determination of specific energy, expended during drilling of channels in the reference sample and in material of the investigated steel structure, in order to the further determination of the strength properties of steel, from which the element is made.The article also presents experimental studies on the determination of strength properties of the structural steels VSt3ps6 and 15HSND, which results have shown the possibility of the determination of strength properties of the investigated material with necessary reliability of the measurements using the proposed method. In particular, there were determined: • yield limit of steel VSt3ps6 and steel 15HSND; • temporary resistance of steel VSt3ps6 and steel 15HSND. During analyzing the domestic and foreign literature it was found that elements of existing steel structures have reserve strength, which is inevitably formed on the basis of designing logic and normative documents, used in steel structures calculations. It was completely confirmed by experimental tests.