BackgroundThe concentrations of circulating adipokines in dogs with myxomatous mitral valve disease (MMVD) have not been investigated in detail.ObjectivesTo determine whether serum concentrations of adipokines differ between healthy dogs and dogs with MMVD and whether circulating concentrations depend on the severity of heart failure resulting from MMVD.AnimalsIn the preliminary study, 30 healthy dogs and 17 client‐owned dogs with MMVD, and in the subsequent study, 30 healthy dogs and 46 client‐owned dogs with MMVD.MethodsProspective case‐controlled observational study. In the preliminary study, serum concentrations of leptin, adiponectin, resistin, visfatin, interleukin (IL)‐1β, IL‐6, IL‐10, IL‐18, and tumor necrosis factor‐α were measured. In the subsequent study, MMVD dogs were divided into three groups according to the International Small Animal Cardiac Health Council (ISACHC) classification, and serum concentrations of leptin and adiponectin were measured.ResultsIn the preliminary study, serum leptin and adiponectin concentrations differed significantly between dogs with MMVD and healthy dogs. Serum leptin (P = .0013) concentrations were significantly higher in dogs with MMVD than in healthy dogs, whereas adiponectin (P = .0009) concentrations were significantly lower in dogs with MMVD. However, we observed no significant differences in the other variables. In the subsequent study, dogs classified as ISACHC class 3 had higher serum concentrations of leptin (P = .0022) than healthy dogs but ISACHC class 1 or 2 dogs did not. Serum adiponectin concentrations were significantly lower in ISACHC class 1 (P < .0001) dogs than in healthy dogs, whereas adiponectin concentrations in ISACHC class 3 dogs were significantly higher than in ISACHC class 1 dogs (P = .0081).Conclusions and Clinical ImportanceCirculating concentrations of leptin and adiponectin might be altered in dogs with MMVD.