Аннотация:The process of hydrolytic polycondensation of diethoxymethylsilane in water under pressure was investigated without the use of organic solvents in non-catalytic conditions and in carbonic acid. It is demonstrated that in both cases the process of the formation of methylsiloxane polymers proceeds with 100% conversion of the monomer and complete preservation of hydrosilyl groups. The conditions for the selective production of linear products were found.