Department of Chemistry, Malaviya Regional Engineering College, Jaipur Manuscript received 4 February 1972; accepted for publication 9 February 1972 Complexation of lead by ethylthioglycolate has been studied polarographically. The reduction of lead in ethyltbioglycolate solution has been found to be reversible and diffasion controlled involving two electron transfer process. Potential vs. concentration data at 0.5 M ionic strength were interpreted on the basis of the formation of three complex species PbA+, PbA2 and PbA3 - employing DeFord and Burne's method. The logarithms of stablity constants of these complexes at 20° and 30° have been calculated and found to be 1.87, 4.39 and 6.40 at 20° and 2.0, 4.47 and 6.83 at 30° respectively.