Background: Uterine rupture remains a major life‑ threatening obstetric catastrophe encountered in many developing countries with its associated high maternal and perinatal morbidity and mortality. It is a major complication in the trial of labour after caesarean section. It is often preventable and predicting the risk of uterine dehiscence/rupture in women undergoing trial of scar will go a long way to improve our knowledge about those women who have low risk. Aim: To determine the lower uterine segment thickness using tranvaginal scan in women with a previous transverse lower uterine segment caesarean section and determine the critical thickness value above which there is low risk of uterine dehiscence/rupture. Study design: The study was a cross-sectional study; participants were pregnant women with a previous caesarean section scar at a gestational age greater or equal to 36 weeks. Setting: Antenatal clinic of University of Ilorin Teaching Hospital, Ilorin, Nigeria. Methodology: A total of 70 pregnant patients with a previous lower uterine segment caesarean section who satisfied the inclusion criteria were recruited from antenatal clinic. Transvaginal ultrasonography was used to assess the thickness of the lower uterine segment and the patients were followed up to delivery. The results were analyzed using SPSS version 21.0 with appropriate tables and figures generated