Objective: Periodontal disease can be a source of subclinical and persistent infection that may induce systemic inflammatory responses that increase the risk of preterm birth. The goal of this study was to establish whether periodontal disease is a risk factor for preterm birth and to evaluate the association of this risk with gestational age. Study Design: This descriptive cross-sectional study included postpartum women with periodontal disease admitted to the maternity care unit of five different medical college hospitals in Dhaka City. Methods: The sample size was 111 postpartum; all of them had mild, moderate, or severe periodontitis. A periodontal examination was performed within 48 hours of delivery to determine the severity of periodontal disease. The outcome variable is preterm birth (define as birth occurring before 37 weeks of gestational age.). The statistical analysis of the data was carried out by using software program SPSS version 17. Results: The prevalence of severe periodontitis was 11.7% (13/111), moderate periodontitis was 36% (40/111), and mild periodontitis was 52.3% (58/111). From the variables that described the socio-demographic characteristics, only age had a significant association with preterm birth, and the mother having a lower age than normal and the mother having higher age than normal had an increased prevalence of preterm birth. From the variables that described the oral health related characteristics, regular visits to a dentist and pain in the tooth had a significant association with preterm birth (P