This study examined the characteristics and dyeing fastness of sheep skins that had been tanned with two different vegetal tannins: hydrolysable tara and condensed quebracho tannins. After tanning, chitosan formate was applied to the leathers in four different proportions. The dye exhaustion and tensile strengths of the leathers increased as the proportion of chitosan formate increased, and the highest levels of both dye exhaustion and tensile strength were obtained in an application at a proportion of 200% on the basis of leather weight. Leathers treated with chitosan formate had slightly higher tensile strength values than the control leathers. In addition, chitosan formate was found to improve waste water parameters such as chemical oxygen demand, total suspended solids, total dissolved solids, salinity, and electrical conductivity Keywords: Chitosan formate, dyeing, leather, quebracho, tara.