The most common causes of young onset dementia are early onset forms of adult neurodegenerative conditions and alcohol. Vascular dementia is the second most common cause of young onset dementia after Alzheimer’s disease. Conventional vascular risk factors may be absent and diagnosis relies on imaging evidence of cerebrovascular disease. Those with suspected young onset dementia should be referred to a neurology-led cognitive disorders clinic where available as the differential diagnosis is considerably broader than in older adults and requires specialist investigation.