Dementia is progressive, age related, chronic condition and can profoundly affect the lives of patients and their families.The main question in care becomes how to promote well being and maintain an optimal Quality of Life QOL. But is not always clear what QOL means.The conceptualizations of QOL vary because most instuments are developed for patients in different stages of dementia, and the relevant life domains for QOL vary with the progression of the disease. As a consequence most instruments are unsuitable for assessing QOL in the whole range of mild to severe dementia.This presents a problem for the daily care for people with dementia and for the evaluation of interventions aimed at improving QOL, as changes in QOL with the progression of the disease are difficult to detect and assess with existing instruments.This presentation following conceptual definition offered. Dementia specific QOL is the multidimensional evaluation of the person environment system of the individual, in terms of adaptation to the perceived consequences of the dementia.