This report is devoted to feature of plasma electrolytic carburising (PEC) of commercial titanium (CP-Ti) to enhance its wear resistance using acetone-based electrolyte. Acetone is known to have a most potential as a carbon source for the PEC of steels and may be an effective component for PEC of CP-Ti. Selection of component provided the electrical conductivity of the solution shows the following. Sodium or potassium hydroxides do not enable to conduct heating to temperatures above 700 ^oC. The probable reason is a high wettability of the metal by these hydroxides which prevents the complete remove of electrolyte from the heated samples. It can be assumed that a partial contact of solution with the heated surface periodically occurs with inevitable cooling of sample. The highest temperatures are reached in 5 % solutions of sulfuric acid or nitric acid that permits to conduct PEC adding acetone. Microhardness of carburised layer is 455 HV using sulfuric acid or 575 HV in nitric one with acetone. The disadvantage of these compositions is an aggressive of acids. It was also found that heating the titanium samples to temperatures above 400 ^oC in a solution of ammonium nitrate or ammonium sulfate can not under any conditions or concentrations. Therefore, ammonium chloride was chosen as conductive component in which the sample temperature of 950 ^oC is reached easily.    Cylindrical samples (Æ 10 ´ 15 mm) of CP-Ti were carburised in an electrolyzer with an axially symmetric electrolyte flow. The carburising of CP-Ti (850 °С, 5 min) in electrolyte of ammonium chloride (10 wt.%) and acetone (10 wt.%) results in the formation of surface layer with thickness of 320 mm and microhardness of 390 HV in which TiO2 (rutile) is found. The increase in microhardness can be explained by dissolution of carbon in titanium with possible carbides dispersed. There is also etching sublayer with a modified structure that is heat affected zone. Therefore, effective diffusion coefficient of carbon in titanium is evaluated assuming that measured microhardness is proportional to carbon concentration in surface layer. Standard solution of the diffusion equation for a semi-infinite body with a constant saturating concentration of carbon on the surface is used. The carbon diffusion coefficient in titanium layer enriched by its oxide is 44 mm2/s at 900 °С, which is greater than the data for glycerol (36 mm2/s), sucrose (43 mm2/s), ethylene glycol (27 mm2/s), and ethanol (33 mm2/s). The surface roughness after processing under these conditions reduces from 0.129 mm (untreated sample) to 0.048 mm. Note also that the PEC of CP-Ti in acetone electrolyte results in the significant improvement of the tribological properties under conditions of dry friction with counterbody of bearing steel (5 N normal load and sliding speed of 0.2 m/s). The friction coefficient decreases from 0.65 for untreated sample to 0.52 for carburised one. In this case, linear wear diminishes by order on sliding distance of 175 m.   The acetone concentration in the electrolyte decreases from 10 wt.% to 6 wt.% during its depletion of 8 hours, which is sufficient for processing of small batch of parts without deteriorating their quality. Specific energy consumption for PEC in acetone-based electrolyte is 160 W/cm2.   This work was financially supported by the Russian Science Foundation (Contract No. 15-1920027) to the Nekrasov Kostroma State University.