Background: The aim of this study was to evaluate the functional capacity of the liver based on the activity of specific enzymes and bilirubin in serum and also to investigate the influence of mechanical and toxic effects of Fasciola hepatica on the structures of the blood vessels and biliary tract in the sheep liver.Methods: Blood samples and liver of 63 indigenous sheep of Pramenka breed, slaughtered in the period from March to December 2009 were used. Based on parasitological findings in the liver, all animals were divided into two groups: control (n=34) and infected group (n=29). For investigation and description of pathological changes in sheep liver, naturally infected with F. hepatica, corrosion cast technique was used.Results: Biochemical analysis of tested parameters showed a significant elevation (P≤0.05) of serum gamma-glutamyl transferase (GGT), total bilirubin (TBIL) and direct bilirubin (DBIL) in infected sheep group comparing with the control group. No significant differences were observed for activity of aspartate aminotranferase (AST) between groups. Vascular and biliary systems of the liver were found to be affected.Conclusion: Results of biochemical analysis are consistent with pathological findings and measuring of tested parameters could be used in early diagnosis of sheep fasciolosis and to test the effectiveness of anthelmintic therapy. Corrosion cast technique is very useful for investigation of pathological changes and neoangiogenesis of vascular and biliary system in sheep liver, caused by mechanical and toxic effects of F. hepatica