Polyhydramnios carries a high rate of complications during pregnancies and adverse perinatal outcomes. The aim of this study was to evaluate the risk of preterm birth in patients with polyhydramnios. Objective: To determine the association of sonographicpolyhydramnios with preterm birth. Methods: A cross-sectional Analytical study was carried out at the Department of Radiology in Sir Ganga Ram Hospital Lahore, Pakistan. Duration of study was from March 2018 to November 2018. Patients in 2nd and 3rd trimester of pregnancy with Polyhydramnios were chosen subsequent to fulfil consideration (inclusion) and rejection (exclusion) criteria. A complete history and investigation were finished. All necessary examination is done. Polyhydramnios confirmed by estimating AFI. Statistical Software for Social Sciences (SPSS version 22.0) is used for the analysis of all data. Standard and Mean Deviation (SD) remained calculated for continuous variables. Results: Total of 64 patients were diagnosed in this study. The Mean ?S.D age was 26.92 ? 3.55 years. Out of 51 patients of 21-29 age group 42 were diagnosed with polyhydramnios and 9 were without polyhydramnios and 23 patients had full-term deliveries and 28 patients had preterm deliveries. In 30?38 age group total 13 patients out of which 10 patients with polyhydramnios and 3 patients without polyhydramnios and 4 patients had full-term deliveries and 9 patients had preterm deliveries. Minimum AFI is 8.0 and Maximum AFI 55.0 with Mean ?S.D of 26.70 ? 9.40. Minimum GA was 141 and Maximum GA 244 days with Mean?S.D of 244.95 ? 27.07. 27. Patients were full-term delivery out of 18 patients have polyhydramnios and 9 patients have no polyhydramnios. 37 patients were preterm delivery out of which 34 Patients have polyhydramnios and 3 patients have no polyhydramnios. Conclusion: This study concluded that excess of amniotic fluid lead towards preterm birth. This is also found patients of 21-29 ages were more prone to polyhydramnios.