Background: The PARPi olaparib has been recently approved as the first targeted therapy available for BRCA-mutated HER2- MBC patients. This meta-analysis aimed to better evaluate the activity, efficacy and safety of single agent PARPi in this population. Methods: A systematic search of MEDLINE, Embase and conference proceedings up to January 31^th2018 was conducted to identify randomized controlled trials (RCTs) investigating single agent PARPi versus chemotherapy (CT) in BRCA-mutated HER2- MBC. Using the random-effect model, we calculated summary risk estimates (pooled hazard ratio [HR] and odds ratio [OR] with 95% confidence intervals [CI]) for progression-free survival (PFS), overall survival (OS), objective response rate (ORR), any grade and grade 3-4 adverse events (AEs) and time to deterioration in quality of life (QoL). Results: Two RCTs with 733 patients were included: the OlympiAD (olaparib) and the EMBRACA (talazoparib). In both trials, physician’s choice mono-CT (i.e. capecitabine, eribulin, gemcitabine or vinorelbine) was the comparator. As compared to mono-CT, PARPi significantly improved PFS (HR 0.56, 95% CI 0.45-0.70) and ORR (OR 4.15, 95% CI 2.82-6.10), with no difference in OS (HR 0.82, 95% CI 0.64-1.05), AEs of any grade (OR 1.37, 95% CI 0.49-3.85) and of grade 3-4 (OR 0.76, 95% CI 0.43-1.33). Use of PARPi was associated with a significant increased risk of anemia (any grade: OR 3.07, 95% CI 1.16-8.10; grade 3-4: OR 7.69, 95% CI 2.55-23.19) and any grade headache (OR 1.57, 95% CI 1.06-2.33), but a reduced risk of neutropenia (any grade: OR 0.53, 95% CI 0.29-0.96; grade 3-4: OR 0.40, 95% CI 0.23-0.67) and any grade palmar-plantar erythrodysestesia syndrome (OR 0.04, 95% CI 0.02-0.10). No significant difference in other types of AEs between PARPi and mono-CT was observed. Patients treated with PARPi experienced a significant delayed time to clinically meaningful QoL deterioration (HR 0.40, 95% CI 0.29-0.54). Conclusions: Single agent PARPi is effective and well tolerated in BRCA-mutated HER2- MBC. Although the optimal sequence is still to be determined, PARPi should now be considered as standard of care in these patients.