The aim of this study was to find out an application of the municipal waste incineration materials and try to use them as a replacement for the natural ones. MSWI (Municipal Solid Waste Incineration) bottom ash (BA) was used as partial/total replacement of siliceous sand in CEM II based mortar. Three size fractions of BA were used with respect to replace the siliceous sand in corresponding way. There were designed 5 mixtures with increasing replacement of siliceous sand by 25 % each. The water/cement ratio was decided to be taken according to the constant consistence of the mortar. The bulk density, compressive strength and bending strength of the mortars were decreasing with growing content of BA.