The amount of technological aids on the market to support people in their everyday functioning is increasing. For example mobile telephone, electronic diary, skyping and domotics. Many of these aids are too complicated to operate for people with cognitive impairments, like dementia. For technology to be practicable and useful for them, it will have to meet certain requirements. This paper addresses the needs and impairments of people with dementia, and the functional requirements for assistive technology for people with dementia.