stated that when animal fats and waste vegetable oils are used for biodiesel production, the sulfur content is expected to be higher due to the presence of sulfur-containing compounds such as proteins. In this study, as seen in Table 1, the sulfur content of the fleshing oil and chicken fat were much higher compared to corn oil. The reason of high sulfur content of the chicken fat may be the sulfur containing protein which may be probably the keratin. On the other hand, high sulfur content of the fleshing oil results from the industrial process of the solid wastes recycle plant where the fleshing oil was obtained because sulfuric acid is used in the fleshing oil production. After the first pretreatment, the sulfur content of the chicken fat was increased. However, the sulfur content of the pretreated chicken did not increase significantly after the second pretreatment reaction. The sulfur content of COME, FOME and CFME were measured to be 138.1, 81.5 and 4.1 ppm,