The polarographic behaviors and the determination of cycasin, glucosyloxyazoxymethane, are described here. In the whole pH range, cycasin shows a reduction wave, which is considered to be due to the reduction of its aliphatic azoxy group. The polarograms from pH 4 to 7 run in two steps, and two electrode reaction mechanisms may be infered. The following facts are observed on the limiting current at pH 1 or 7: It is controlled by the diffusion process, and its temperature coefficient has a value resembling that of the usual diffusion current. The wave height shows a linear proportionality to the concentration of cycasin. The contents of cycasin in cycad seeds, determined polarographically, are presented, and compared with the results obtained by the paper chromatographic method.