The rapid progress in engineering enhances the demands set on materials requiring better mechanical properties, resistance to frictional wear, resistance to corrosion and erosion etc. These demands can be satisfied by e.g. applying various surface engineering techniques which permit modifying the microstructure, phase and chemical composition of the surface layers of the treated parts. A significant progress has been made in this area in terms of technological innovation, production of new coating materials and development of design systems. A prospective line of the development is the production of multicomponent and composite layers by introducing new gaseous atmospheres, such as e.g. vapours of metalorganic compounds, and by combining (in a way justified from the point of view of the cost involved) various surface engineering methods. These layers improve essentially the performance properties and service life of the treated parts and widen significantly the application range of the materials, including titanium and its alloys which are now being increasingly used in industry. The glow discharge assisted treatments and the so-called multiplex techniques permit modifying the microstructure and the phase and chemical compositions of the surface layers produced on titanium alloys, and controlling the residual stress state that prevails in them so as to improve the performance properties of these alloys, such as the frictional wear resistance (without impairing their high corrosion resistance), and the resistance to oxidation at elevated temperatures. The paper discusses the results of structure examinations and the phase and chemical compositions, frictional wear and corrosion resistance of titanium alloys with surface layers of the types: Al2O3+TiAl3+TiAl+Ti3Al and TiN+(Ti,Ni)(3)P+Ti3P+(Ti,Ni) producing by duplex surface treatments. The glow discharge assisted techniques, developed in the present study, permit producing surface layers of the diffusion character with a precisely specified structure, surface topography, chemical and phase composition tailored to suit the increasing use of titanium alloys in medicine and also in power-generation industry.