Objective: To determine the relationship between periodontitis and preterm labour in pregnant women presenting to a tertiary care hospital in Lahore. Methods: This case control study was conducted at Obstetrics & Gynecology Unit 4 of Sir Ganga Ram Hospital, Lahore for six months. The delivering women, who consented to participate, were divided into two case and control groups. For each case one control was enrolled who met the inclusion criteria, so total sample size was 380 women. Women delivered before 37 weeks of gestation were case group and those delivered after 37 weeks were control group. A patient was considered having periodontitis if she had probing pocket depth of ≥3mm in at least 3 sites. Data was collected and analyzed on SPSS version 21. Results: In this study the mean age of the case group patients was 28.52±6.45 years while of the control group was 28.67±6.35 years. The mean value of probing depth pocket in the case group was 3.872±1.37 while the mean value probing depth pocket of the control group was 3.58±1.52. Out of 380 patients the periodontitis was found in 275 patients. The odds of having periodontitis in case group was 1.85 times higher than control group i.e. OR=1.85[1.17-2.92]. Conclusion: Periodontitis is a preventable risk factor of preterm labour in women presenting at a tertiary care hospital. Keywords: Preterm Labour, Periodontitis, dental hygiene, preterm delivery