Nivolumab, a fully human immunoglobulin monoclonal antibody inhibiting the programmed cell death protein-1 receptor, demonstrated robust efficacy and a manageable safety profile across multiple tumor types in clinical trials. The aim of the present study was to investigate the efficacy and safety of nivolumab for pretreated patients with non-small cell lung cancers in clinical practice. In this observational monocentric retrospective study, 98 patients were enrolled between February 2015 and February 2016. The global median overall survival was 6.34 months (95% confidence interval (CI) : 4.11-10.88) and the global median progression free survival was 1.84 months (95% CI: 1.68-2.73). In the univariate analysis, clinical performance status score was the only factor significantly correlated with overall survival. The safety profile of nivolumab is consistent with that described in prior studies, with only 7% undesirable effects requiring the discontinuation of treatment. The results of the present study demonstrate that nivolumab affords clinical efficacy and manageable tolerability in patients with non-small cell lung cancers.