The influence of different ratios of fillers addition such as limestone and micro white sand, as well as nano-titania particles on the physico-mechanical properties of ordinary white Portland limestone cement (OWPC), has been studied. One mix (10.00 wt. %) of equal ratios from limestone and white sand in micro scale, partially replaced by cement clinker. Mechanical strength, phase composition, and microstructure of blended cement have been investigated. The results showed that filler reduces the setting time and total porosity, improve the strength, free lime content, combined water content and bulk density of cement pastes due to the pozzolanic effect of micro white sand that replaces clinker and enhance an excess amount of hydration products. It can be concluded that limestone fills the pores between cement particles due to the formation of carboaluminate, while micro sand increases the hydration C-S-H product. TiO2 nanoparticles (i.e., less than 100 nm) shows a great efficiency in enhancing the mechanical strength of cement paste due to the incorporation efficiency of nanoparticles as active sites for gel Tobermorite C-S-H fibers growth during hydration,