Two oxidation waves are observed at mercury electrodes for tetraphenyllead in dichloromethane. The mechanisms of the oxidation processes have been investigated by dc and differential pulse polarography. The first wave is a broad two-electron step and represents the summation of a number of processes related to mercury exchange and halide abstraction. The exchange reactions are as follows: 2 Φ4Pb + Hg→2Φ3Pb+ + Φ2Hg+2e- 2 Φ3Pb+ + Hg→2Φ2Pb2+ + Φ2Hg+2e- Dichloroethane and HgCl2 are identified as products of controlled potential electrolysis experiments as well as Φ2Hg and Φ2PbCl2 implying that the coordinatively unsaturated Φ3Pb+ and/or Φ2Pb2+ react with the solvent dichloromethane and abstract chloride. The second oxidation process is the two electron step. Φ2Hg+Hg→2 ΦHg+ + 2e-. Tetraalkyllead compounds (tetramethyl, tetraethyl, tetrabutyl) also give rise to related electrode processes at mercury electrodes and polarographic techniques may form the basis of a method for their analytical determination if separated chromatographically prior to detection.