There has been an increasing interest in depositing metal or metal-containing thin films through plasma polymerization for various applications. This work deals with the plasma graft polymerization of tetramethyltin (TMT) on polypropylene surfaces with an aim of producing special electrical and optical coatings. The fragmentation of TMT under cold plasma conditions and the recombination of discharge-generated active species were studied by analyzing the resulting molecular mixture trapped outside of the plasma zone by HR-MS and GC-MS techniques. It was found that the predominant ionic fragment is m/z = 165, and the most probable intermediate structure of the polymer formation mechanism is hexamethylditin. The structure of polymeric layers deposited on various substrates were investigated by ESCA and FT-IR methods. Intense oxidation of tin-based polymeric layers were observed under open laboratory conditions. The existence of weak Sn-Sn and Sn-C bonds in the polymeric structures is suggested to be responsible for this reaction. This phenomenon was associated with enhanced UV transparency. Based on analytical data a plasma-enhanced polymerization mechanism of TMT is proposed.