In this study, variations in permeability of a gold ore by nut shell addition was studied. Ore particle size, nut shell size and volume fraction in the ore were the parameters investigated. Permeability is an important issue in heap leach operations considering the processing duration. Particularly below 6 mm particle size permeability is greatly hampered. Turkey is the leading country in the world in hazelnut production. Therefore, considerable amounts of nut shell are obtained as a by-product. Incerase in the permeability of a finely crushed ore will obviously enable an increase in the leaching efficiency. The finer the particle size the more the liberation of gold is yet the permeability is lower. Therefore, this study focuses on the possibility of improving the permeability of ore heaps with nut shell addition. Optimum amount of nut shell which should be added to the ore was found to be 5% by volume. It was found that the permeability of ore crushed below 2.36 mm considerably increased by the addition of nut shell below 18 mm.