Aggression is common in older people with mental illness, with 15–43% of community referrals to old age psychiatry services and 44–65% of older people with Alzheimer's disease living in the community exhibiting such behaviour. In psychiatric in-patient units, assaults on staff are most common on wards for elderly people with organic mental illness. There is little high-quality research into the management of aggressive behaviour in dementia. We consider the available literature, which has shown certain behavioural measures and different classes of medication to be of benefit. We discuss factors associated with violence in elderly people with mental illness and potential management options.