BackgroundHepatic circulatory disturbances have been associated with obesity and fatty liver in humans. In the veterinary literature, however, there is limited information regarding the effects of different body condition scores (BCS) on liver hemodynamic indices in dogs.ObjectivesTo investigate the influence of BCS on liver hemodynamic indices.AnimalsFifty‐three client‐owned dogs of various breeds were included.MethodsProspective observational study. Dogs were divided into 3 BCS groups using a 5‐point scale: G1 – 12 ideal dogs, G2 – 21 overweight dogs, G3 – 20 obese dogs. Mean portal velocity (MPV), portal blood flow volume (PBFV), portal congestion index (PCI), hepatic artery resistivity index (HARI), and hepatic vein (HV) spectral wave were obtained by pulsed Doppler sonography. Alkaline phosphatase (ALP), gamma‐glutamyl transferase (GGT), and alanine aminotransferase (ALT) activities were determined. Liver enzymes activities and liver hemodynamic indices were compared among groups.ResultsObese dogs had lower MPV, higher percentage of abnormal hepatic vein spectral wave and higher median ALP activity than did ideal dogs (P < 0.05). Overweight and obese dogs had lower PBFV than ideal dogs (P < 0.01). Overweight dogs had higher median GGT activity than ideal dogs (P < 0.05). No difference was observed for PCI, HARI and median ALT activity among the groups.Conclusions and Clinical ImportanceObesity was associated with changes in portal vein indices and in HV spectral wave. These changes were accompanied by significant differences in some liver enzymes activities and could be a sign of early liver disease.