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Method of obtaining oligo(organosiloxanes) comprizing hydrolytic polycondensation of chlorosilanes or their mixts. in a water-free active medium, boiling of the reaction mass and distg. off the solvent, in which chlorosilanes used are compds. having formula Y3-nSiCln, (n = 1-3, Y is monovalent hydrocarbon substituents -CH3, -C2H5, -C3H7; -C4H9, -CH=CH2, -C6H5), or -H, reactive medium is a mixt. of urea with 1,3-diketone selected from acetylacetone, acetoacetate, malonate in aprotic solvents, condensation is carried out at boiling temp. during 1-5 h, after cooling Schiff base hydrochloride ppt. and target product is sepd. from soln. by known methods. Thus, polysiloxane oligomer with mol. mass 6200 was obtained in 89% yield by copolycondensation of phenyltrichlorosilane, methyltrichlorosilane, methyl(phenyl)dichlorosilane and dimethyl(vinyl)dichlorosilane carried out at molar ratio SiCl/urea/acetylacetone=1.0:1.0:1.0 in hexane.