Work-related upper limb and neck musculoskeletal disorders (MSDs) are one of the most common occupational disorders around the world. Although ergonomic design and training are likely to reduce the risk of workers developing work-related upper limb and neck MSDs, the evidence is unclear. To assess the effects of workplace ergonomic design or training interventions, or both, for the prevention of work-related upper limb and neck MSDs in adults. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, AMED, Web of Science (Science Citation Index), SPORTDiscus, Cochrane Occupational Safety and Health Review Group Database and Cochrane Bone, Joint and Muscle Trauma Group Specialised Register to July 2010, and Physiotherapy Evidence Database, US Centers for Disease Control and Prevention, the National Institute for Occupational Safety and Health database, and International Occupational Safety and Health Information Centre database to November 2010. We included randomised controlled trials (RCTs) of ergonomic workplace interventions for preventing work-related upper limb and neck MSDs. We included only studies with a baseline prevalence of MSDs of the upper limb or neck, or both, of less than 25 . Two review authors independently extracted data and assessed risk of bias. We included studies with relevant data that we judged to be sufficiently homogeneous regarding the intervention and outcome in the meta-analysis. We assessed the overall quality of the evidence for each comparison using the GRADE approach. We included 13 RCTs (2397 workers). Eleven studies were conducted in an office environment and two in a healthcare setting. We judged one study to have a low risk of bias. The 13 studies evaluated effectiveness of ergonomic equipment, supplementary breaks or reduced work hours, ergonomic training, a combination of ergonomic training and equipment, and patient lifting interventions for preventing work-related MSDs of the upper limb and neck in adults.Overall, there was moderate-quality evidence that arm support with alternative mouse reduced the incidence of neck/shoulder disorders (risk ratio (RR) 0.52; 95 confidence interval (CI) 0.27 to 0.99) but not the incidence of right upper limb MSDs (RR 0.73; 95 CI 0.32 to 1.66); and low-quality evidence that this intervention reduced neck/shoulder discomfort (standardised mean difference (SMD) -0.41; 95 CI -0.69 to -0.12) and right upper limb discomfort (SMD -0.34; 95 CI -0.63 to -0.06).There was also moderate-quality evidence that the incidence of neck/shoulder and right upper limb disorders were not reduced when comparing alternative mouse and conventional mouse (neck/shoulder RR 0.62; 95 CI 0.19 to 2.00; right upper limb RR 0.91; 95 CI 0.48 to 1.72), arm support and no arm support with conventional mouse (neck/shoulder RR 0.67; 95 CI 0.36 to 1.24; right upper limb RR 1.09; 95 CI 0.51 to 2.29), and alternative mouse with arm support and conventional mouse with arm support (neck/shoulder RR 0.58; 95 CI 0.30 to 1.12; right upper limb RR 0.92; 95 CI 0.36 to 2.36).There was low-quality evidence that using an alternative mouse with arm support compared to conventional mouse with arm support reduced neck/shoulder discomfort (SMD -0.39; 95 CI -0.67 to -0.10). There was low- to very low-quality evidence that other interventions were not effective in reducing work-related upper limb and neck MSDs in adults. We found moderate-quality evidence to suggest that the use of arm support with alternative mouse may reduce the incidence of neck/shoulder MSDs, but not right upper limb MSDs. Moreover, we found moderate-quality evidence to suggest that the incidence of neck/shoulder and right upper limb MSDs is not reduced when comparing alternative and conventional mouse with and without arm support.