Olaparib, niraparib, and rucaparib are the three primary poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors that are currently available in the market. Previous studies indicate different incidences of adverse events based on the PARP inhibitor or country. This study used data from the United States Food and Drug Administration Adverse Event Reporting System collected between January 2018 and December 2023. The data analyzed in this study involved patients receiving PARP inhibitors for treating ovarian cancer. A comparative analysis of the three PARP inhibitors was conducted using the reporting odds ratio (ROR) and the adjusted ROR (aROR) controlling for patient background differences. The aROR for niraparib was significant at > 1.000, including platelet count decreased ( This study indicates that the types of adverse events may vary by PARP inhibitor and by country. These results will be beneficial in clinical practice.