Objective To evaluate the effects of neuromuscular blocking agents( NMBAs) in acute respiratory distress syndrome( ARDS) . Methods Randomized controlled trials( RCTs) and non-RCTs were recruited fromPubMed( 1966. 1-2012. 3) , EMBASE( all the years) , Cochrane Library( all the years) and CNKI Database( 1979-2012) . Related published studies and attached references were hand searched. All the RCTs and non-RCTs ( including prospective and retrospective studies) about NMBAs for the patients with ARDS were included. Then a meta-analysis and statistic descriptions for RCTs( using RevMan5. 0 software) and non-RCTs were performed. Jadad and NEWCASTLE-OTTAWA QUALITY ASSESSMENT SCALE were used to assess the methodological quality of the included RCTs and non-RCTs. Results Three eligible RCTs and four non-RCTs were enrolled. The quality of the included trials was high. Pooled analysis for three RCTs showed that NMBAs significantly reduced 28-day mortality [ OR 0. 58, 95% CI( 0. 39, 0. 86) , P = 0. 007] and increased ventilator-free days within 28 days [ WMD 1. 91 d, 95% CI( 0. 28,3. 55) , P =0. 02] in ARDS compared with the control group. Conclusion The present meta-analysis indicates that NMBAs reduce the 28-day mortality and increase ventilator-free days within 28 days in ARDS.