Purpose: PARP inhibition is an exciting new anticancer strategy. As the first PARP inhibitor approved for the treatment of advanced BRCA-mutated ovarian cancer, olaparib has proven to be effective in the treatment of several solid tumors. We performed a meta-analysis of published randomized controlled trials to evaluate the efficacy and safety of olaparib in cancer patients. Methods: PubMed, Embase, and oncology-conference proceedings were searched for relevant studies. End points were overall survival (OS), progression-free survival (PIPS), overall response rate (ORR), and grade 3/4 adverse events. Pooled hazard ratio (HR)/risk ratio (RR) and 95% CI were calculated using random or fixed-effect models. Results: Eight trials involving 1,957 patients were ultimately identified. The pooled analysis demonstrated that olaparib treatment significantly improved PFS (HR 0.62, 95% CI 0.47-0.82; P=0.001), OS (HR 0.82, 95% CI 0.73-0.93; P=0.001), and ORR (RR 1.38, 95% CI 1.16-1.65; P<0.001) when compared with therapy not containing olaparib. This association was further confirmed by sensitivity analysis. Additionally, olaparib treatment offered a significant survival benefit for patients with BRCA mutation. Moreover, treatment with olaparib was associated with a significant increase in risk of severe anemia. Conclusion: Olaparib treatment has better treatment response compared with therapy not containing olaparib, whereas olaparib can increase the risk of severe anemia.