Chemical stabilization is defined as modification of engineering properties of soil with chemical reactions of various additives. Chemical stabilization is applied to the soils which cannot be adequately treated by mechanical stabilization. Chemical stabilization leads to changes in soil properties such as strength, plasticity, compaction and durability, as well as in its permeability. Permeability of soil is important in ground water flow and leakage problems. However, there are few studies about the effect of chemical stabilization on permeability. In this study, the effects of chemical stabilization with lime and perlite combinations on permeability of high plasticity clayey soil were investigated. With the stabilization of high plasticity clayey soils with lime, the permeability of the mixture increases up to 25 times. Moreover, perlite which can be used as a secondary additive in stabilization of such soils causes serious decrease in permeability..