Background: Knowing transient vascular perfusion abnormalities of testes after open inguinal herniotomy procedure is essential for the surgeon who is mainly responsible for the patient outcome. Purpose: To assess the effect of open inguinal herniotomy procedure on the testicular blood supply in children using duplex ultrasonography (DUS). Material and Methods: A prospective observational study included 60 boys (mean age ¼ 9.46 14.46 months; age range ¼ 2 months–6 years) who underwent open inguinal herniotomy operation. Using DUS, the testicular volume, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) were calculated preoperatively and one week, one month, and six months postoperatively. The pre- and postoperative measurements were compared. Statistical analysis was performed using v2 test, Fisher’s exact test, or Student’s t-test when appropriate. Results: On physical examination, the hernias were unilateral in 57 boys and bilateral in three boys. Comparison between testicular volumes preoperatively and postoperatively showed no significant change (P > 0.05). There was a statistically significant increase of PSV and RI one week and one month postoperatively (P < 0.0001) but returned to be near to the preoperative values at six months. As regards EDV, there was a slight but non-significant postoperative increase (P > 0.05) which did not return to the preoperative value. Conclusion: The affection of testicular vascularity postoperatively is transient and returns to be near to the preoperative values in the late postoperative period (six months postoperatively). Additionally, no significant change in testicular volume postoperatively. Keywords Testicular vascularity, inguinal herniotomy, children, duplex ultrasonography