A caesarean section is often done when vaginal birth might jeopardize the baby's or mother's life or health, however it has been performed on request in recent years. The rate has grown to at least 25%. One of the serious complications after cesarean section is development of uterine dehiscent scar. To assess the possible causes of dehiscent scar in pregnant ladies with previous one cesarean section. Observational cross-sectional prospective study, carried out from the beginning of January 2020 to December 2020, at Elwiya Maternity Teaching Hospital - Baghdad. Two hundred fifty patients were enrolled in the study, full history was taken regarding their previous scar, and they were fully assessed regarding current pregnancy and all patients were followed up during cesarean section and afterwards. The rate of dehiscent scar was (12%). It is found that the rate was significantly inversely related to the time space between pregnancies; higher incidence of dehiscent scar in those women whose interpregnancy interval was 6 months or less while the lowest incidence in those whose interpregnancy interval was ≥ 12 months. Significant relationship has been found with the type of hospital, as women whose previous cesarean section was performed at the general hospitals were less likely to have dehiscent scar than those at private hospital, with gestational age of ≤ 36 completed weeks in both the previous and the current cesarean section and with the trial of labor before performing cesarean section. Failure of progress is an important risk factor associated with uterine scar dehiscence. Cesarean sections performed at or before 36 completed weeks gestation in the previous pregnancy were associated with higher rate of uterine scar dehiscence in the current pregnancy. Previous cesarean sections performed in private hospitals were associated with higher rate of uterine scar dehiscence in the current pregnancy.