The Mini-Mental State Examination (MMSE) was developed in 1975 as a brief test for the quantitative assessment of cognitive impairment in adults. It has since been widely used by physicians throughout the world. Its main use is for screening for cognitive impairment, which is a significant cause of morbidity and mortality in the elderly. The MMSE is also used for follow-up of cognitive changes in patients suffering from dementia and as a research instrument for assessing the efficacy of drug treatment in Alzheimer's disease. The MMSE examines orientation, immediate and short-term memory, attention and calculation, language and praxis. Construct validity of the test is considered good. An MMSE score of < or =23 or less is generally accepted as indicating cognitive impairment and was associated with the diagnosis of dementia in at least 79% of cases. The major variable that affects the MMSE's sensitivity is the level of cognitive impairment. The attainment of high levels of sensitivity increases with increased impairment. Specificity was found to be between 80-100%. Disadvantages of the MMSE include difficulty to identify mild cognitive impairment and difficulty in recording changes in cases of severe dementia. Furthermore, age, education, cultural and socioeconomic background can cause a considerable bias in the MMSE's scores. This paper aims to review the MMSE, highlight advantages and disadvantages, and describe possible clinical applications of the test.