The anodic lead(II) oxide studied was formed in 0.1 M NaOH solution (60 degrees C) at 0.2 V (vs. Hg/HgO) on a lead electrode. The composition of the oxide film, characterized by X-ray diffractometry and cyclic voltammetry, is mainly tet-PbO, and small amounts of Pb2O3 and PbOx (1 < x < 2). The mechanism of formation of the oxide film was investigated using chronoamperometry. If was found that the oxide film forms by a diffusion mechanism. The results of ac impedance investigations show that the oxide film is an n-type semiconductor. The donor density and flat-band potential of the oxide film are 3.73 x 10(16) cm(-3) and -0.79 V respectively.