Elution of mercury (Hg) from fly ashes and the stabilized fly ashes of municipal waste plant were examined by the leaching test prescribed in the Japanese Environmental Agency Notification No. 13, 1973 (JLT-13) . On elution, a sample of the stabilized fly ash yielded over 0.005 mg/L of Hg, whereas that of the unstabilized ash yielded less than 0.0005 mg/L of Hg. Then, these samples were mixed with several chelating agents, and the Hg elution process was studied. Experimental results indicate that the elution yield of Hg from the stabilized fly ash depends on the Hg content in the fly ash and the combination of chelating agents used.