The electrochemical deposition of poly(vinylferrocene) films by oxidation of CH2Cl2 solutions of the neutral polymer has been studied by use of the electrochemical quartz crystal microbalance. Application of a potential step to potentials where ferrocene sites are oxidized results in immediate precipitation of polymer. There is a very rapid change in frequency. The rate of frequency change is greater than would be predicted by the deposition of one ferricinium perchlorate unit per electron removed. At longer times, the frequency response levels off to a value below that anticipated on the basis of subsequent voltammetric characterization. The contributions of both solvent and polymer properties to these effects are discussed.