Nowadays, soil compaction has become a significant subject of study due to agricultural mechanization. It is necessary to find methods for avoiding adverse effects of soil compaction. The effect of using organic material and natural or artificial modifiers on soil behavior has been studied by scientist. In the present study, the effect of using natural zeolite (Clinoptilolite) on soil physical and mechanical properties was investigated. At the first part, the combinations of two soil textures (clay loam and loam), two moisture content level (0.9 PL and 1.1PL) as a fraction of plastic limit (PL) and four levels of zeolite (0, 2, 4 and 6% db) were used to determine shear strength parameters (cohesion and angle of internal friction), bulk density and water retention curve parameters (n, ?, ? r and ? s ) of repacked soil samples. First, the soil samples were poured into a metal cylinder and were loaded by an axial load of 180 kPa for 30 min by CBR apparatus. Then, small core samples were taken out of this large soil volume for determination of soil properties. To determine shear parameters, a straight shear test was used and to determine retention curve parameters at four suctions (5, 10, 30, and 40 kPa) a Sand-Kaolin box was used. High suctions (100, 200, 500, and 1000 kPa) was measured by pressure plate apparatus. The dry bulk density was also determined by taking a additional core. In the second part, the combined effects of soil texture (clay loam and loam) and four levels of zeolite (0, 2, 4 and 6% db) on maximum dry bulk density and corresponding critical moisture content were quantified using Proctor compaction test with 5 blows per layer. The compaction tests were done at different moisture contents (which were determined according to the consistency limits). The shear box results showed that soil cohesion decreased and angle of internal friction increased with zeolite addition. Soil cohesion decreased 9% by using of 6% natural zeolite, and the angle of friction increased by 13%. Clay loam soil with 1.1PL moisture content had more cohesion and the angle of friction was less. Loamy soil with 0.9PL moisture content had low cohesion and high angle of friction. Dry bulk density decreased 4.1% by using of 6% natural zeolite. Loamy soil had more dry bulk density than clay loam. With increasing soil moisture content from 0.9PL to 1.1PL the dry bulk density increased by 10%. The soil water retention curve parameters were affected by soil texture, moisture content and zeolite treatments With increasing soil moisture content n, ? r , and ? s decreased. Clay loam soil had more ? r analogues to loamy soil. The ? r increased 33.8% by using of 6% natural zeolite. Results of the second phase showed that critical moisture content increased 6.6% by using of 6% natural zeolite. Dry bulk density decreased with increasing natural zeolite but its variation was not significant. Loamy soil