Limited reports have been found describing heart diseases in donkeys; it is unclear whether this shortage arises from low incidence of heart disease in donkeys or because of the diagnostic challenge especially with the absence of typical clinical signs of cardiac disease in donkeys. The purpose of this study was to establish the normal reference range of echocardiographic measurements of cardiac structures in healthy donkeys using both two-dimensional (2D) and M-mode techniques. Thirty adult clinically healthy donkeys free of cardiovascular disease were used. Standardized 2D and M-mode echocardiographic examinations were performed in nonsedated standing donkeys. Mean, range, standard deviation, and coefficient of variation were calculated for the cardiac parameters. Pearson correlation coefficient was used to determine the correlation between the obtained measurements and body weight. Reference range of normal echocardiographic measurements was established. Weak linear correlation between the echocardiographic measurements and body weight was reported in left ventricular internal diameter in diastole and systole. The reported reference values of echocardiographic measurements and indices may be helpful in diagnosing donkeys with cardiac disease.