The aim of this study was to investigate serum leptin and ghrelin levels and their relations with circulating cortisol, thyroid hormones, lipids, homocysteine (Hcy) and folic acid in dogs with compulsive tail chasing (CTC). The material of this study consists of fifteen dogs with CTC and 15 healthy controls of various weights, breeds, ages of both sexes were enrolled in the study. CTC was diagnosed on the basis of the dog's behavioral history, clinical signs, and results of other medical assessments. None of the dogs were considered to have concurrent medical disease that would account for CTC. Dogs with CTC had a higher leptin (8.3 +/- 0.9 ng/mL vs 1.7 +/- 0.2 ng/mL, P<0.001) and lower ghrelin levels (74 +/- 7 pg/mL vs 144 +/- 41 pg/mL, P<0.05) than those of healthy controls. Serum cortisol, lipids (cholesterol, phospholipids and NEFA) and Hcy levels increased (P<0.05), whereas serum folic acid decreased (P<0.001) in dogs with CTC as compared with controls. Serum ghrelin correlated negatively with cholesterol (P<0.05), but serum leptin correlated positively with cholesterol, fT4, and phospholipids (P<0.05). These results suggest that serum leptin and ghrelin levels may bring up a new perspective on our understanding of the pathophysiological mechanisms associated with CTC. Serum levels of both hormones may be associated with serum levels of lipids and free T4.