Background: Prematurity is the leading cause of infant mortality worldwide. Correct and appropriate evaluation of cervical status has become important in predicting spontaneous onset of labor with widespread use of ultrasonography in obstetrical practice. Objective: To evaluate the cervix clinically and ultrasonography during pregnancy as a preterm birth predictor. Patients and methods: This was a prospective observational study included one hundred and twenty four pregnant women. The participants were divided in to two groups: Group A included 82 pregnant women had previous history of preterm birth with or without other risk factor, and Group B: included 42 pregnant women with no risk factors for preterm birth with and with prior normal labor. All cases were selected from Obstetrics and Gynecology Department, Al-AzharUniversityHospital (Al-Hussein) during the period from January 2021 to July 2021. Result: There was a significant difference between the groups in term of preterm labor history, short cervix, threatened abortion, interval ≤18 months and vaginal discharge that they were significantly more frequent in group A. The predictive role of cervical length measurement in mm was evaluated by ROC curve between 20 to 24 weeks. Cervical length ≤25mm has sensitivity 100%, specificity 64%, PPV 52.4% and the NPV 100%. The cervical length was significantly lower in group A compared to group B. There was a significant difference between preterm and term delivery of preterm labor history, and short cervix. Conclusion: The role of ultrasound in the prediction of preterm birth, cervical length, low anterior thickness, fundal thickness and posterior thickness were found to be significant predictors of preterm delivery. Cervical length measured in transvaginal sonography has acceptable consistency for screening and early diagnosis of spontaneous preterm deliveries in low risk women.