Background: Preterm birth, defined as childbirth occurring at less than 37 completed weeks or 259 days of gestation from the first day of the last menstrual period, is the major determinant of neonatal mortality and morbidity worldwide and remains a public health concern. Of the estimated 3 million neonatal deaths occurring globally each year, about 1 million are directly related to prematurity. No studies have been carried out locally to determine the prevalence as well as determinants of preterm delivery in Rwanda. This study aimed to determine the prevalence and risk factors associated with preterm birth among women admitted in the delivery service of Nyamata District Hospital located in Bugesera District, Rwanda. Methods: This was a health facility-based cross-sectional study that used data collected from July to August 2019 through structured interviews and medical records. A total of 400 women were enrolled into the study at Nyamata District Hospital. Study participants’ socio-demographic, psychological and medical characteristics were described using frequency tables. Bivariable and multivariable logistic regression models were fitted to determine factors associated with pre-term birth using SPSS version 21. Results: The prevalence of preterm birth in Nyamata Hospital was found to be at 9%. Most of respondents 78.8 % were aged between 20 to 35 years. Almost a quarter of respondents had a Body Mass index below 18.5 and a quarter had Mid-Upper Arm Circumference below 24cm. lower weight gain during pregnancy (OR: 3.89, CI: 1.10–13.77), MUAC below 24cm (OR: 5.85, 1.26-27.24), shorter inter pregnancy interval (OR: 7.60, CI: 1.10–52.43), and perception of high level stress during pregnancy (OR: 7.68, CI:1.37–42.92)were some of the factors associated with preterm birth negatively and having health insurance coverage (OR: 0.27; CI: 0.08-0.83) was a protective factory. Conclusion and recommendation: In this study, the prevalence of preterm birth in Nyamata Hospital was found to be high. Factors indicating nutritional deficiency of pregnant mothers such as, lower weight gain during pregnancy and MUAC below 24cm plus shorter inter pregnancy interval and perception of high level of stress during pregnancy were associated with preterm birth. Policy makers and health planners of Rwanda should arrange health system mechanisms which can address good nutritional supplement of pregnant mothers. The health system of Rwanda should also work on improved utilization of family planning methods for optimal spacing of child birth and improved conditions which can relived stress of pregnant mothers.