This study investigates the effect of Multiwalled carbon nanotubes (MWCNTs) on the mechanical properties of Cement mortar. A diameter of 20 nm and a length of 10 microns MWCNTs were used in this study. Different proportions of MWCNTs used in this study were 0.05, 0.10, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, and 0.5 % of by weight of cement. Ultrasonicator was used to disperse the MWCNTs.The compressive strengths of the hardened samples were determined after 7, 14 and 28 days of water curing. Results show that 0.25 % of MWCNTs is the optimum dosage for achieving maximum Compressive strength. © IAEME Publication