By using various physical methods (gravimetric, electrochemical and other) were investigated the suppression process of corrosion of carbon steel in natural and technological waters with saturated dicarboxylic acids (adipic, malonic and succinic) and its dihydrazide. It is known, to use as a corrosion inhibitor hydrazine H2N - NH2, whose action is based on binding the oxygen dissolved in water, and thereby reducing the corrosive activity of the water: N2H4 + O2 → 2H2O + N2. However, a known inhibitor possess significant drawbacks. Firstly, the effect of hydrazine becomes noticeable either at a sufficiently high temperature (80 - 1000C) or with the additional administration of certain catalysts, such as salts of cobalt, copper, manganese. Secondly, it is toxic, and work with him should be very careful. All of this complicates the work of closed water systems. The used acids are solid, well crystallizable substances, well soluble in water. Their chemical properties are linked primarily by the presence of carboxyl groups. All those reactions which involve the residues of fatty acid, also, occur in a series of dibasic acids. However, in this series there are new reactions that are caused by the mutual influence of the two carboxyl groups or become possible due to the special position of these groups The applied substances in an amount of 0.05 - 1.0 g/L significantly reduced the corrosion metal loss of steel in water closed pipeline. They are significant hampered the anodic process, shift the stationary potential in a positive side, contribute to the formation on the corroding surface protective coating layers. Acids themselves, their dihydrazides and its decomposition products initially are adsorbed on the corroding steel surface, complicating the process of ionization of the metal, and then interact in solution with ionized ferrous and ferric, forming various complexes. Insoluble complexes are included in the oxide - hydroxide film formed on the corroding metal surface, filling its pores, thereby substantially increased the protective properties of the coating layers. The reduction degree of the corrosion loss depends on concentration of inhibitor and testing time, and in some cases exceed than 15 times. It should emphasize the ecological safety of the proposed inhibitors.