Aim:To obtain the incidence of preterm premature rupture of membranes (PPROM) at Siriraj Hospital during 2012-2016 and to identify its possible risk factors in singleton pregnancies. Methods: This study was a retrospective case-control study. The institutional ethical committee has approved the study. The medical records of eligible cases were reviewed. To assess the risk factors of PPROM, the data of the cases with PPROM in 2016 were compared with the data of pregnant women who did not have PPROM and delivered at term. Fifteen variables of interest were studied. Results: During the 5-year period, there were 43 727 deliveries at Siriraj Hospital and 1280 (2.93%) cases had PPROM. In 2016, 252 pregnant women were diagnosed PPROM and data of 199 cases were compared with the data of 199 control cases. Mean latency period was 2 days and mean gestational age at birth was 34.7 weeks in PPROM group. Logistic regression analysis showed that diabetes mellitus, poor weight gain and history of previous preterm birth were the factors that significantly associated with PPROM, with adjusted odds ratio (OR) 3.22 (95% confidence interval [CI] 1.47-7.05), 2.58 (95% CI 1.63-4.07) and 8.81 (95% CI 2.81-28.69), respectively (P < 0.05), while multiparity decreased the risk of PPROM (adjusted OR = 0.36, 95% CI 0.23-0.57) (P < 0.001). Conclusion: The incidence of PPROM during 5-year period was 2.93%. Diabetes mellitus, poor maternal weight gain and history of previous preterm birth significantly increased risk of PPROM while multigravida reduced the risk.