The objective of this study was to evaluate the effect of the racial crossing on scrotum-testicular biometric characteristics of four sheep Santa Ines and four crossbred (Santa Ines x Dorper) submitted to scrotal insulation, following the return of these characteristics to values previously reported. For this, two measurements were made regarding the scrotal circumference (SC), length (L) and testicular width (W) before treatments. The testicular volume (V) was calculated by the formula V=2 [(r2) x π x H]. The pouches were made with double-layer plastic, internally lined with cotton, and fixed around the spermatic funiculus and scrotum with adhesive tape and bandage remaining in this position for seven days. Measurements were made every seven days, totaling 15 measurements throughout the experiment. The data were submitted to analysis of variance (ANOVA) to a randomized block design with two blocks, 15 treatments and four replications. The variables analyzed were subjected to Dunnett test at 5% probability, to compare the values obtained before and after insulation. For comparison between the breeds, the variables were submitted to Tukey test at 5% probability. All animals studied suffered significant influence (P<0.05) after scrotal insulation, but Santa Ines returned to the values previously observed in a shorter period than the crossbred. In summary, sheep Santa Ines have a higher resistance than crossbred animals when subjected to thermal stress induced by scrotal insulation.