Introduction: Prevalence of violent incidents-physical or verbal directed to self or others, is a serious problem in psychiatric setting1. Violent behavior in psychiatric unit affects the safety of patients and any other team member working in that particular setting. There is evidence that majority of the nurses working in psychiatric setting have been attacked by patients at least one time in their career.2 Aim: To estimate the prevalence of aggression and violence among clients admitted in psychiatric units and also to find out the factors associated with aggressive and violent behavior. Materials & method: A comprehensive search was made on ProQuest, CINAHL, PubMed, Google scholar, and Cochrane databases for published original research articles between 1990 and 2016. We included all types of studies that reported about incidence or prevalence of violent behavior and factors associated with it in psychiatric ward. Result: Twenty one studies were eligible for meta-analysis and the overall pooled prevalence of violence among patients admitted in psychiatric ward is 16% (0.13. 0.19, CI 95%, i-squared=97.9%, p=0.000). The review also examined the causes accompanying with violent behavior. Conclusion: Violent behavior in psychiatric setting appear to be extremely variable between different settings. Assessing prevalence of violent behavior and to find out factors associated with violent behavior are a vital part of developing aggression management and violence prevention training program to safeguard clients and staffs from violent behavior.