The present case report deals with treating one such platinum-sensitive first relapse of high-grade serous ovarian carcinoma with a poly (ADP-ribose) polymerase (PARP) inhibitor. Here, rucaparib, one of the Food and Drug Administration (FDA)-approved PARP inhibitors, was used to treat platinum-sensitive relapse in a patient with germline breast cancer (BRCA) negative ovarian cancer. The patient showed a complete response to the treatment and was in remission for around 11 months with only one dose reduction and no blood transfusion.