In order to examine the effect of exogenous melatonin on selected blood indices, dairy goats were given pineal gland hormone at a dose of 0.1 mg/kg body weight. Next, one and four hours after the melatonin had been administered, blood samples were collected from the goats in the control and treated groups in order to determine the levels of glucose, total cholesterol, triacyloglycerides, free fatty acids, as well as alanine and aspartate aminotransferase. The pineal gland hormone caused a significant increase in the levels of glucose, total cholesterol, triacyloglycerides and the activity of alanine aminotransferase. After melatonin administration a significant decrease in the FFA:TAG and FFA:Cholesterol blood ratios was observed. Moreover, no changes in the free fatty acid concentrations and the activity of aspartate aminotransferase were observed.