Portland cement consists essentially of compounds of lime mixed with silica and alumina whereas zeolite is a kind of minerals containing high content of reactive silica and alumina. Therefore, there is a probability to apply zeolite in cement mortar in order to develop mortar properties. The purpose of this research was to study and analyze the efficiency of zeolite addition on properties of cement mortar. X-ray diffraction (XRD), universal testing machine (UTM) and scanning electron microscope (SEM) were used to characterize for mortar specimens. Mechanical property test was compressive strength according to ASTM C109 and carried out on 5 x 5 x 5 cm3 cube specimens at 1, 7 and 28 curing days. In this research, cement mortars were prepared by mixing type I Portland cement, fly ash, sand and zeolite. Zeolite was varied as 0, 0.25, 0.50 and 0.75 wt.% to cement and w/b (water to binder ratio) was 0.48. The results presented that the compressive strength of mortar with small amount of zeolite was improved since 1day age obviously comparing to that of mortar without zeolite. It was confirmed that zeolite would help strengthening the cement mortars at early strength.