The relationship between suicide and dementia has not systematically been investigated, although the prevalence of both, dementia and suicide, increases with age. In contrast to patients with other psychiatric disorders, patients with dementia were not found to die from suicide more often than expected (SMR, 0). Thus the diagnosis of dementia does not contribute to the elevated suicide risk in old age. In studies using the psychological autopsy method, dementia was rarely diagnosed in suicide victims. Suicide attempts were observed in less than 1% of all patients with dementia. Depression as an important common risk factor of suicide and dementia is often found in patients with Alzheimer's disease (0% to 86%) as well as in patients with multi-infarct dementia (20% to 45%). However major depression was found significantly more often in vascular dementia than in dementia of Alzheimer type. Suicidal thoughts and intents, wishes to die and feelings that life is not worth living were reported in 1% to 42% of all patients with dementia, especially if these patients also suffered from depression. This review comprehensively presents the association between cognitive deficits, insight in early stages of dementia and suicidality and possible confounders which have not systematically been investigated up to now.