The primary objective of our study was to investigate the effectiveness and safety of olaparib maintenance therapy in patients with BRCA-mutated recurrent ovarian cancer in daily practice. The secondary objective of this study was to identify prognostic factors associated with prolonged progression-free survival (PFS) in such patients. We conducted a retrospective analysis of 40 patients who received olaparib maintenance treatment. Data on clinicopathological factors, oncological outcomes, and adverse events were obtained from medical records and analyzed. All patients had high-grade serous recurrent ovarian cancer with BRCA mutation and achieved complete or partial response to the most recent platinum-based chemotherapy. After a median follow-up of 14.3 months, the median PFS was 23.7 months (95% confidence interval, 14.1-33.4); however, the median overall survival was not reached. In the log-rank test, the PFS was significantly longer for patients with most recent platinum-free interval (PFI) ≥ 12 months, complete response to the last platinum-based chemotherapy, and less than three lines of previous chemotherapy (p = 0.005, p = 0.016, and p = 0.023, respectively). Most hematologic and non-hematologic adverse events were of grade 1 or 2, and the common adverse events were mostly related to myelosuppression. Olaparib maintenance treatment in BRCA-mutated recurrent ovarian cancer is effective and safe in clinical practice. Most recent PFI, response to the last platinum-based chemotherapy, and the number of previous chemotherapy lines were associated with PFS in patients with BRCA-mutated recurrent ovarian cancer.