Background: cesarean scar niche is one of the novels mentioned complications of cesarean section due to the rising numbers of cesarean sections and improved imaging modalities. The causes of cesarean scar niche are still being investigated, one of them is the uterine closure method that should be studied to pick up the best one to decrease the incidence of niche after cesarean delivery. Objective: The aim of this work was to find the best way of uterine closure decreasing the incidence of cesarean section niche. Material and methods: A prospective randomized controlled study that was conducted between May 2021 and April 2022 at the department of Obstetrics and Gynecology, Zagazig University. Full term ninety-eight primigravida undergoing first elective cesarean section were equally randomized to either purse string or double-layer unlocked suture. Six months after cesarean section, Sonohysterography was done for assessment of cesarean scar integrity. Markers of cesarean scar healing included residual myometrial thickness "RMT", niche depth "D", hypoechoic triangular niche width "W” and healing ratio "D/RMT". All these markers were calculated by experienced sonographers who were not aware of the uterine closure technique. Results: In terms of estimated blood loss, there was no significant differences between both groups. However, frequency of appearance of niche in purse-string group was 25% compared to 56.8% in the double layer group (P=0.002). The mean thickness of the residual myometrium covering the defect was significantly higher 7.8 ± 1.1 mm after purse-string than 5.9 ± 0.6 mm after a double-layer closure (P = 0.001). The mean healing ratio in purse-string group was 0.449 versus 0.600 in the double-layer closure (p<0.001). Conclusion: Purse-string uterine closure was associated with better uterine scar healing, higher residual myometrial thickness and lower rate of cesarean scar defect than double layer closure.