An anodic voltanmetric study was made of the Ziegler-Natta catalyst in tetrahydrofuran using a rotating platinum electrode. It was shown that these measurements could be used as an indication of the activity of the catalyst. It was also observed that the catalyst and the cocatalyst (diethyl aluminum chloride) formed an electrochemically inactive species. The study was complicated by the presence of an impurity (probably water) In the solvent that reacted with the catalyst and by the formation on the electrode of an inert film.