There is no test available to measure German GPs' knowledge of dementia. Existing English questionnaires cannot be transferred to the German setting and do not focus on the GPs' specific problems and tasks. The management of dementia patients and their relatives both involves psychiatric and GP expertise. Therefore, we asked psychiatrists with a specialty in geriatric psychiatry and experienced GPs to assess 59 multiple-choice questions. The concordance of responses in each expert group and for each question, their ratings of relevance for the GPs' situation on a sixtier scale and their comments on each question served as the basis for the selection of the final 37 items concerning 11 dementia subjects. After pilot testing has been completed, this set of questions will be sent to GPs in three German regions in an attempt to get a general idea of German GPs' knowledge of dementia and to analyze the psychometric properties of the test.