The purpose of this study was to determine and compare the Vertebral Heart Size (VHS) and Cardio-Thoracic Rate (CTR) in normal Wistar Rats. The size of the organs in the chest cavity and the size of the heart can be measured by taking thorax radiographs. Thorax radiographs of 85 male Wistar rats were taken under anesthesia, and VHS and CTR were calculated in the digital environment. The mean VHS was 7.22 mm in the right lateral position and 7.34 mm in the left lateral position. In the radiography taken in the ventrodorsal position (P = 0.3530), the mean CTR was calculated as 0.89 mm. Also, no significant correlation was measured between VHS and CTR. In conclusion, our study results can be reference values, as no previous study has been found for Wistar rats.