Background <p>This prospective clinical trial aimed to compare the effects of single-layer versus double-layer uterine closure techniques on cesarean scar healing in women undergoing repeat cesarean delivery.</p> Methods <p>Seventy women aged 18–50 years with a history of at least one prior cesarean delivery were randomized into two groups: single-layer non-locking closure (<i>n</i> = 35) and double-layer non-locking closure with surgical refreshing of the incision edges (<i>n</i> = 35). The primary outcome was residual myometrial thickness (RMT) measured by transvaginal ultrasonography at six months. Secondary outcomes included RMT at six weeks, healing ratios, presence of niche, operative time, transfusion need, infectious morbidity, and hospital stay duration. Sample size was based on preliminary data indicating a mean RMT of 5&#xa0;mm (SD 0.6&#xa0;mm). To detect a 0.5&#xa0;mm difference with α = 0.05 and β = 0.8, 26 participants per group were required; 35 were enrolled per group.</p> Results <p>At six months, the double-layer group had significantly greater RMT (5.1 ± 0.4&#xa0;mm vs. 4.1 ± 0.4&#xa0;mm; <i>p</i> &lt; 0.001). Similar findings were seen at six weeks. Operative time was shorter in the single-layer group. However, this group required more frequent additional uterine suturing due to suboptimal tissue approximation or bleeding, which did not significantly extend operative duration. Hemoglobin levels and hospital stay were comparable. Transfusion was needed in one patient in the single-layer group and three in the double-layer group.</p> Conclusion <p>Double-layer closure with surgical edge refreshing was associated with improved cesarean scar healing based on RMT.</p> Trial registration <p>ClinicalTrials.gov NCT03644433. Registered on 06 July 2018.</p>