Mental health clinicians are often asked to determine an individual's risk of future violence. Dangerous assessments are required in a wide variety of situations that include involuntary commitments, emergency psychiatric evaluations, seclusion and restraint release decisions, inpatient care discharges, probation/parole decisions, death penalty evaluations, domestic violence interventions, fitness for duty evaluations, and after a threat is made. This article provides an overview regarding the assessment of dangerousness in both adults and juveniles and a summary of recent research regarding the relationship of mental illness to violence. (c) 2006 Elsevier Ltd. All rights reserved.