This paper presents the effect of using pozzolanic material as a new stabilizing agent on shear strength and swelling properties of unsaturated clayey soil. Three clayey soils were selected from the northern part of Jordan and used for this research. Different percentages of pozzolanic material by dry weight of the soils namely; 2.5%, 5.0%, 7.5% and 10.0% were added to the selected soils. Atterberg's limits tests, pr octor density test, direct shear test, unconfined Compression test, swelling pressure test and swell potential test were conducted on specimens treated with pozzolan. It was found that the increase in pozzolanic material will decrease the plasticity index and increase the unconfined compressive strength of the soils use. Furthermore, the addition of 10.0% of pozzolanic material by dry weight of the soil could eliminate both the swelling pressure and the swell potential of the used soils.