In this research, cement mortar specimens were prepared with sand to cement(1:2.75) and (1, 2, and 3 wt%) of ceramic oxides (MgO, ZnO and Al2O3) at different particlesizes (11.8, 38.8, 109.8 nm), respectively. At curing time (7days), the (structural, thermaland physical) characteristics of the mortar specimens were investigated.The dry density and porosity results show that the values of density increased by(23.4, 15.6, and 9.5%), and the values of porosity decreased by (76.2, 63.8, and 56.2%) for(MgO, ZnO, and Al2O3), respectively with respect to the reference mortar specimen. Thethermal conductivity results show that the values of thermal conductivity decreased by(47.27, 40.66, and 51.16%) for (MgO, ZnO and Al2O3) respectively, with respect to thereference mortar specimen . Results of characterizations tests (XRD and optical microscope)showed that the reference mortar specimen has high roughness with large number ofCa(OH)2 crystals, as well as the presence of pores, while after adding the nanopowders, itshowed a decrease or disappearance of Ca(OH)2 and produced homogeneous structure ofcalcium silicate hydrate compound (C-S-H), in addition to a large decrease in the pores andsurface roughness. This explains the significant improvement in the properties of cementmortar mixed with nanopowders, hence these mortars were very appropriate for coveringwalls, buildings and other outdoor building applications.