In this study, it was examined whether the radiographic measurements taken from the tarsal region, especially the calcaneus, can be used in sex determination. In addition, two different horse breeds were used and whether these values would cause any difference between the breed was examined. 213 race horses were used in this study. Radiographic images of the left tarsal joint of Arabian horses (30 females, 57 males) and Thoroughbred horses (57 females, 69 males) were taken from the lateromedial direction. The widest point of the trochlea was seen to be a determinant in sex determination of Arabian horses. In Thoroughbred horses, it was seen that the value of the calcaneus body was the most important factor in sex determination. As a result of the discriminant analysis, 71.26% of male and female Arabian horses and 66.67% of Thoroughbred horses, respectively were classified correctly. It was observed that 88.26% of the horses between the two breeds were classified correctly regardless of sex. In the correlation test between measurements, negative correlation value with age was seen in the talus measurement (correlation value:-0.139-099). In conclusion, radiological measurements of this clinically important region can be used as an alternative method for sex and breed discrimination.