Electropolymerization of chloromethylchlorosilanes, [ClCH2Si(CH3)3-mClm (m = 1, 2)], using sacrificial anodes to produce linear and branched polycarbosilanes consisting primarily of -Si-C- repeating units, is reported. Detailed spectroscopic characterizations of the oligomers and polymers with GPC, NMR, and IR are given. GC-MS analysis of the electrosynthesis products reveals at least twenty oligomeric structures. It is shown that many structural irregularities (i.e., crosslinking, loop, fused rings, and others) are also incorporated into the branched skeleton of polycarbosilanes. The formation of these diverse structures, molecular weight and reaction yield are strongly dependent on the electrosynthesis conditions, the anode material (Mg, Al and Zn), solvent and supporting electrolyte. Thus, high molecular weight (Mn ~ 57,000) of highly branched but soluble poly[methylsilylene-methylene] (PMSM) has been obtained by electropolymerizing ClCH2Si(CH3)Cl2 with an Al/nickel (anode/cathode) pair in the THF/HMPA (5/5) / Bu4N+BF4-. The electrosynthesis yields a soluble polycarbosilane (25 –35%) with a bi-modal molecular weight distribution along with an insoluble fraction (10 – 30%). Cyclic voltammetric analysis suggests that electroreduction of chlorocarbosilanes undergoes an ECE mechanism to initiate polymerization, as well as a myriad of side reactions.