Leptin is a hormone that coordinates body weight control and is produced by adipocytes. In this study, Yüzüncü Yıl University research and application farm of leptin in the Nord and Tahirov grown on sheep breeds, and some vitamins and the correlation between them for the purpose of determining the levels of some biochemical parameters was made. In the study, 2 different healthy sheep breeds (Norduz, Tahirova) were used. A total of 26 sheep, 13 of each sheep breed, were included in the study. The levels of Leptin, Vitamins A, D and E, glucose, urea, total protein, FT3 and FT4 were examined in blood samples taken from animals. The leptin and FT4 levels were 15.92 ng/ml and 1.07 µg/dl, respectively, in the Tahirova sheep breed, while these values were 5.22 ng/ml and 0.91 µg/dl in the Norduz sheep, and the difference in value was found to be statistically significant (p<0.001). A negative correlation was found between alpha Decopherol and total protein and FT3 in Tahirova sheep, and a positive correlation was found between vitamin D3 and retinol. Decibels were found to be negative in Tahirova sheep. In the Norduz sheep, a negative correlation Dec detected between retinol, vitamin D3 and leptin, and a positive correlation Dec detected between FT4 and FT3. By looking at the results of this study, it shows that the detection of high serum leptin levels in the Tahirova breed, which is one of the thin-tailed sheep, theoretically does not depend on the tail fat ratio of leptin production. In order to explain the biochemical mechanisms of such phenomena in sheep with thin and fat tails, additional feeding-hormone studies are needed.