Water resistance of leather is an important property to several applications, like footwear and clothing with high wearing comfort even under wet and cold conditions. Furthermore, leather, which has absorbed too much water, loses its ability to insulate against heat and cold, Therefore, waterproof leather used for footwear should not uptake more than 25 % 30 % of water. However, the leather should allow additionally high water vapour permeability and some reversible water up-take to remove Perspiration from body. To understand how to prevent the wetting of leather, it is necessary to understand the process of leather wetting. Generally, it takes place in four-steps  

– Water spreads over and wets the leather surface;

– Water penetrates into the leather;

– Water wets the fiber network (i.e. internal surface of leather); – the leather soaks by water due to the attractive interaction between water and leather. Not only collagen backbone, but also tanning agents, dye molecules, salts, and other materials which present in leather network, might be involved in these interactions. There are many polar functional groups in collagen fibers such as –OH, –COOH, –NH2and –CONH–. The chemical compounds to be added mostly are Hydrophilic and have good water affinity. Therefore, to improve water resistance property several leather making processes and leather surface modifications are applied.