Jiaxing Huang,1,2,* Yaxiong Zhang,1,2,* Jin Sheng,1,2,* Hongyu Zhang,3 Wenfeng Fang,1,2 Jianhua Zhan,1,2 Ting Zhou,1,2 Ying Chen,1,2 Lin Liu,1,2 Li Zhang1,2 1Department of Medical Oncology, Sun Yat-Sen University Cancer Center, 2State Key Laboratory of Oncology in South China, 3Department of Medical Oncology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, Guangdong, People’s Republic of China *These authors contributed equally to this work Background: Nivolumab (BMS-936558/ONO-4538) was the first monoclonal antibody targeting programmed death (PD)-1. So far, a number of clinical trials on nivolumab have showed satisfactory efficacy in treating non-small-cell lung cancer (NSCLC). Herein, we present a meta-analysis evaluating the efficacy and safety of nivolumab for previously treated advanced NSCLC patients. Methods: Electronic databases were searched for eligible literature. Data of objective response rate (ORR), disease control rate, overall survival, progression-free survival, and adverse effects (AEs) were extracted and pooled. Outcomes analyzed and presented in this study were according to the original data from nivolumab 3 mg/kg. Results: In general, nine trials with 817 patients were included in this meta-analysis. The pooled ORR, disease control rate, 1-year overall survival rate, and 1-year progression-free survival rate were 20% (95% confidence interval [CI]: 17%–23%), 36% (95% CI: 22%–51%), 47% (95% CI: 40%–53%), 21% (95% CI: 18%–24%), respectively. In addition, the rate of grade 3–4 AEs was only 8% (95% CI: 6%–12%). Subgroup analysis showed no significant difference in terms of ORR between squamous and non-squamous NSCLC (odds ratio 1.23, 95% CI: 0.63–2.39, P=0.51). However, significantly greater ORR was presented in programmed cell death ligand 1 (PD-L1) positive cohort (ORR 31%, 95% CI: 24%–38%), compared to PD-L1 negative cohort (ORR 12%, 95% CI: 9%–17%). The odds ratio for objective response to nivolumab in PD-L1 positive cases relative to negative cases was 3.08 (95% CI: 1.87–5.08, P<0.0001). Conclusion: In conclusion, nivolumab is a promising second-line agent for previously treated advanced NSCLC with manageable AEs. Both squamous and non-squamous NSCLC patients showed similar efficacy. In addition, patients with positive PD-L1 expression had better response from nivolumab. Microabstract: We present a meta-analysis evaluating the efficacy and safety of nivolumab for previously treated advanced NSCLC patients. In our study, nivolumab is a promising second-line agent for previously treated advanced NSCLC with manageable AEs. Both squamous and non-squamous NSCLC patients showed similar efficacy. In addition, patients with positive PD-L1 expression had better response from nivolumab. Keywords: nivolumab, PD-1, non-small-cell lung cancer (NSCLC), meta-analysis