¹Harran University, Faculty of Veterinary, Department of Internal Medicine, TR-63100 Şanlıurfa - TÜRKİYE DOI : 10.9775/kvfd.2023.29887 Canine Visceral Leishmaniasis (CVL) and Canine Monocytic Ehrlichiosis (CME) are zoonotic diseases that cause coagulation disorders, abnormalities in various organs and systems along with vasculitis. Since it was reported that the presence of co-infection may cause more severe abnormalities, this study aimed to investigate the synergistic effects of co-infection on some coagulation analytes (prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) and D-Dimer). Twenty dogs, all were mixed breed, aged 2-4 years, and determined to be co-infected with CVL and CME were used. As a result of the coagulation profile analyte measurements, the values of APTT, PT, and the concentration of FIB were determined to be higher in the Co-infected Group compared to the Control Group (p<0.05). Receiver operating characteristic (ROC) analysis revealed that PT (AUC: 0.980); APTT (AUC: 0.959), FIB (AUC: 1.000), and D-dimer (AUC: 0.929) had outstanding diagnostic discrimination. As a result, it was concluded that the presence of co-infection deteriorates the coagulation profile more severely in co-infection with CVL and CME. Keywords : Activated partial thromboplastin time, D-Dimer, Dog, Fibrinogen, Prothrombin time