This study was performed to propose a suitable treatment for waste foundry sand (WFS) before persistent disposal. It was observed that solidification/stabilization (S/S), which is the common pre-treatment method because of its comparatively easy and inexpensive applicability, can treat WFS including dissolved organic carbon (DOC) above hazardous landfilling limits. Regular sand was partially replaced with WFS with a ratio of 090?wt% in order to prepare three different kinds of mortar samples, where Portland limestone cement (PLC) alone, calcium lime (CL) alone, and PLC together with CL were contained as binders. Leaching behaviors of all S/S products were analyzed according to the TS EN 12457-4 leaching test. The treatment efficiency was assessed to reduce the DOC content to the levels under the European landfill acceptance criteria. Furthermore, heavy metals (Ni, Zn, Cr), fluoride (F-), total dissolved solids leachability, and total organic carbon content were analyzed in order to investigate the pre-treatment ability and to determine whether S/S products can be disposed of in a landfill site with municipal wastes or in a separate landfill site. The results showed that S/S of WFS is an efficient pre-treatment technique before its disposal in a landfill and provides economical advantages compared to hazardous waste landfilling.