Background: Rupture of the membrans before labor is called premature rupture of membrans. When the mother has premature rupture of membrans and is not given antibiotic therapy, the bacteria will enter the uterus and cause infection. Infection in infants will pose a serious risk to health because it will cause permanent damage to the lungs, and brain and can even cause death. In addition, mothers who are not given antibiotics will experience uterine infections which will cause fever and bleeding. Irrational use of antibiotics will lead to antibiotic resistance. Based on this description, it is necessary to evaluate the use of antibiotics in patients with premature rupture of membrans. This study aims to evaluate the rationality and effectiveness of antibiotics in patients with premature rupture of membrans at Bumiayu General Hospital. Methods: This research was conducted in a descriptive non-experimental observational manner with retrospective data collection. The number of samples used was 80 patients. Analysis of the results is presented in the form of tables and percentages. Results: The pattern of antibiotic use in patients with premature rupture of membrans by the intravenous route was cefazoline (41.25%), ceftriaxone (18.75%), cefotaxime (8.75%), ampicillin (2.5%), while the use of antibiotics by the oral route was cefadroxile (82.5%), erythromycin (10%), cefixime (5%), metronidazole (5%) and amoxicillin (2.5%). The rationality of using antibiotics in patients with premature rupture of membrans was obtained, namely 100% right indication, 100% right patient, 100% right drug, 100% right dose and 100% right route of administration. Conclusion: The use of antibiotics in patients with premature rupture of membrans has been rational. The effectiveness of using the drug was 100% because it was seen from the decrease in leukocyte values in laboratory data.