Cathodic and anodic plasma electrolytic saturation of steels with boron is carried out in vapour-gaseous media which is formed in some aqueous solutions under required conditions. Electrolyte containing sodium tetraborate (borax) and sodium hydroxide is used for the cathode boriding. For example, treatment of steel H13 at 960°C for 10 min results in the formation of a boride layer (FeB and Fe2B) with thickness up to 25 μm and microhardness of 1930 HV. The layer thickness can be increased to 105 μm using a pulsed voltage with a frequency of 10 kHz and duty cycle of 40%. The two-component saturation of steels with boron and carbon (borocarburising) in solutions of borax and glycerin enables to reduce the content of brittle FeB boride which has a beneficial effect on the wear resistance of borided steel. Boronitriding in a solution containing borax and sodium nitrite as well as boronitrocarburising using the electrolyte of borax and carbamide are also tested.  Anodic boriding can be carried out in borax-based solutions, but the best results are obtained using boric acid. In this case, an oxide layer and a boride-martensitic layer are formed on the surface of the steel samples being cooled in the electrolyte. The layer thickness on steel 45 is 170 microns with a maximum microhardness of 1800 HV. A lower hardness of 1000 HV was obtained after anode boroncarburising of steel 20 in an electrolyte containing boric acid, glycerol and ammonium chloride.  All these processes of plasma electrolytic saturation of steel with boron and other elements result in an increase in the wear resistance of steels. This fact is observed in sliding of a hard ball (silicon carbide, aluminum oxide, zirconium oxide) on the samples surface or in friction of the treated and untreated samples on the hardened steel disk as counter-body. It is shown that the weight wear rate of the borided or borocarburised steels was 2–16 times lower in comparison with untreated samples. These results are confirmed by measurements of the track profile of friction and photographs of worn surfaces. As a rule, the formation of a hardened layer leads to a change in the wear mechanism from abrasive or fatigue wear to adhesion one.  The exterior layer containing iron oxides and retained austenite is suggested to have a good running-in and sufficient ductility while the hard borides and martensite prevent from surface layer deformation. Therefore, the porous oxide layer can play a positive role by retaining the lubricant.  Corrosion resistance of steels after their electrolytic-plasma saturation with boron and other elements increases according to the tests in tap water or sodium chloride solution. Potentiodynamic measurements showed a shift of the corrosion potential in the positive direction and a decrease in the corrosion current density. This effect is enhanced by the use of a pulsed voltage with a frequency of 10 kHz, which is explained by the decrease in the nanocrystal sizes of the boride layer from 100–160 nm at a constant current up to 65–105 nm in samples borided at the optimum mode of pulsed treatment. The results of the measurements are confirmed by the data of electrochemical impedance spectroscopy, according to which the minimum diameter of the capacitive loop is observed in the untreated sample while the maximum one is related to the sample borided for 30 min. An increase in the oxidation resistance of low-carbon steel Q235 after its borocarburising in borax and glycerol solution has also been found.