Slope stability is one of the most important problems in geotechnical engineering because failure could cause catastrophic environmental and human disaster, in addition to large economical losses due to such failure. There are different techniques used for stabilizing slopes and to increase the slope safety factor, such as rubble, slope stabilizing piles. Slopes could fail under different types of external loads, changing in the surrounding environmental conditions such as the water table and many other reasons could cause such failures in the slope. The simplest solution to handle with slope failures is to avoid the failed zones and choose safer locations to move the projects which are decided to be constructed nearby the failed slopes. But this solution could not be applied in most cases with the increase of populations and the construction activities. For this reasons many stabilizing systems were introduced in order to stabilize slopes and to increase the slope safety factors to avoid expected failure. The choice of an adequate stabilizing system should be based on geological and hydrological explorations and a comprehensive site investigation considering the most economical system and materials availability. The purpose of this paper is to investigate the effect of geofoam on soft clayey slopes which contain weak layers. The analysis of the embankment is performed by the limit equilibrium analysis program (Slide V6.003). The main factors which affect the slopes stabilized with geofoam such as, geofoam width, thickness, and position of the geofoam from the road level are also presented and discussed.