We report our experience in the management of a relapsed ovarian cancer patient with somatic RAD51C mutation, treated with olaparib monotherapy. The patient was diagnosed with stage 4 high-grade serous ovarian carcinoma and was treated with neoadjuvant chemotherapy, cytoreductive surgery, and postoperative chemotherapy. After a second cancer recurrence, she underwent FoundationOne CDx testing following disease progression on multiple lines of chemotherapy. Based on the FoundationOne CDx results, olaparib monotherapy was started. After 13 months of therapy, all lesions responded to the treatment, and she achieved complete response as demonstrated by normalization of the levels of CA125 and positron emission tomography-computed tomography (PET-CT). We plan to continue olaparib monotherapy until disease progression.