This paper presents results of field and laboratory permeability tests aimed at evaluating the performance of mineral barriers for the containment of organic liquids (Non Aqueous Phase Liquids, NAPL). Experimental landfills were constructed following optimal ranges of variation of soil index properties proposed previously and the performance of the landfills was evaluated under two distinct weather conditions (rainy and dry periods). A primary test campaign was performed during the rainy period (March to August). Then a second testing campaign was performed from November 2013 to January 2014 (months of low rainfall). The obtained results corroborate several results published in the technical literature: fluids with a low dielectric constant (non polar) tend to present higher intrinsic permeability (K) than polar fluid sand the presence of water, the most wettable fluid, reduces the NAPL permeability. Soils with a higher plasticity index, IP, presented higher Kw/KNAPL, (ratio water/NAPL intrinsic permeability) showing that the values of K are dependent on the interactions between solid particles and interstitial fluid. Based on laboratory and field results, optimal ranges of variation of soil index properties are proposed for the construction of mineral barriers for organic liquid containment.