Polarographic studies of Ni(II) ion complexed with monoethanolamine, MEA, in aqueous solution have been carried out using sodium perchlorate as a supporting electrolyte. With use of D. C. and A. C. polarograms polarographic behaviors of the complex have been discussed. The wave obtained from basic solutions are found to be well defined and reversible, while reduction of the complex at pH smaller than 8.8 seems to be kinetic controlled with different complex species. Reducing species of the complex on the mercury electrode is determined to be $Ni(MEA)_3OH$ instead of $Ni(MEA)_2(OH)_2$ which is reported by other workers. Overall stability constant of $Ni(MEA)_3OH$ is obtained to be $10^{20}.$