In several species, the vertebral heart scale (VHS) measurement is frequently used to provide a more objective evaluation of cardiomegaly. However, normal-sized parameters for radiographic measures of the cardiac silhouette in Siberian weasels (Mustela sibirica) have not been determined. Right lateral (n = 24) and ventrodorsal (n = 20) thoracic radiographs from free-ranging Siberian weasels with clinically normal cardiac and pulmonary function were acquired and evaluated to determine the specific VHS for the Siberian weasel. The mean (SD) VHS of the right lateral (RL) and the ventrodorsal (VD) views were 6.70 (0.60) and 6.95 (0.69), respectively. VD view radiographs had a considerably higher VHS than RL view radiographs, and RL view measures were less variable than VD view values. The VHS of Siberian weasels was unaffected by age, body weight, or sex. The results determined in this study can be used in clinical diagnostic and radiographic evaluations of Siberian weasels.