This study was conducted on 17 horses to investigate the effects of suspected piroplasmosis on serum biomarkers indicative of heart injury. The horses were diagnosed based on clinical and para-clinical examinations. After taking medical histories, blood samples were collected from the jugular vein and serum was separated. Additionally, samples were taken from 16 healthy horses with similar nutritional and management conditions to serve as a control group. Serum biomarkers of heart injury, including cardiac troponin, CK-MB isoenzyme, LDH, and AST, were measured. The mean cardiac troponin levels in the control and affected horses were 0.022±0.01 and 0.048±0.03, respectively, showing a significant difference between the groups (p=0.001). The mean CK-MB and AST levels were significantly higher in the affected group compared to the control group (p=0.001 and p=0.000, respectively). The LDH serum activity in the control group was lower than in the affected group, but the difference was not statistically significant (p=0.202). In conclusion, the findings suggest that suspected piroplasmosis increases serum levels of cardiac troponin and other biomarkers of heart injury.