The Mini Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (MDRS) are among the most commonly used screening tests for dementia. The goals of our study were, firstly, to identify sociodemographic factors which may explain the variance of test results in a community sample and, secondly, to investigate the interrelationship of these two dementia screening tests in order to evaluate the concurrent validity. A total of 1947 subjects were investigated in the setting of the Austrian Stroke Prevention Study (ASPS). Our study confirms most previous results demonstrating a relationship of higher dementia test scores with both younger age and higher educational level. Interestingly, the results we obtained suggest only a weak relationship and poor concurrent validity of the two tests. The total scores of the two tests show poor joint variance. This could lead to the conclusion that these tests evaluate different cognitive domains.