Background: several studies using various methods have been conducted to evaluate the correlation of lower uterine segment measurement with the risk of uterine rupture or dehiscence with relative success.Objective: to compare the accuracy of transvaginal ultrasound versus transabdominal ultrasound to assess the lower uterine segment thickness at term.Patients and methods: our study was conducted on 100 patients admitted for elective C.S. The patients were subjected to complete general, obstetric examination and ultrasound measurement of lower uterine segment by TAS on partially full bladder and by TVS on empty bladder, and measuring actual thickness intra-operative.Results and conclusion: Data from the present study demonstrated the superiority of TVS over TAS for the assessment of LUS thickness. Measurement of LUS thickness by TVS, if incorporated into guidelines on the management of women who have undergone a previous cesarean, could provide valuable information in planning for delivery and counseling women undergoing VBAC, by predicting its safety and success. It has the potential to be a useful addition to management protocols for women who have previously delivered by cesarean section.