Abstract – In this investigation, treatment of sludge obtained from tannery industries, which contain potentially heavy toxic metals, organics, was characterized and the performance of the solidification/ stabilization (S/S) of the sludge was discussed. The heavy metal characteristics of the sludge were determined by means of AoAc 990.08.2005 test, as defined in both USEPA regulations. S/S studies were conducted using fly ash to solidify the sludge containing high concentrations of total moisture content, volatile solids, Mn, Cd, Pb, Zn, Fe, Ni, Cu, Cl, Total Cr, Cr3 and Cr6. The raw sludge stabilized by using lime. To identify the optimum stabilization limit. The waste/blinder ratios of 36 sludge specimens were cured at room temperature for 3,7,14 and 28 days. The compressive strength of the specimen was measured to determine the feasibility of using solidified sludge as safe land fill. The heavy metal and organic contents of the extracts, of each specimen were determined in concentrations which were lower than the standard concentration in USEPA 1311 and 200.8 leaching procedure for the most part.