BACKGROUND: The current thrust toward evidence-based practice requires the use of systematic evaluations of clinically relevant research to guide practice. OBJECTIVE: The aim of this systematic literature review was to identify the significant factors associated with violence and aggression on inpatient psychiatric units. DESIGN: The databases Cumulative Index toNursing and Allied Health Literature (CINAHL), PsycINFO, and Medline were searched using the key wordsaggression and/orviolence. Studies included in the review were those that were published between 1992 and 2002, conducted on inpatient psychiatric units, used a prospective design, and provided the reliability and validity of the measurement tools. RESULTS: Twentyseven articles were reviewed. The findings were organized into the following categories: patient-related variables, staff-related variables, unit-related variables, interactional variables, and studies related to prediction of aggression and violence. CONCLUSIONS: The findings indicate that (a) much of the available evidence supports the experienced clinician’s knowledge of who is at risk for becoming aggressive on inpatient psychiatric units; (b) among factors shown to be related to violence, some can be modified and others cannot; and (c) there is a critical need for well-designed nursing research that takes into account the complexity of the problem of aggression and violence on inpatient psychiatric units.