The Bayer Activities of Daily Living Scale (B-ADL) has been developed on an international basis to assess deficits in the performance of everyday activities. The scale's main target group is community dwelling patients who suffer mild cognitive impairment or mild-to-moderate dementia. It comprises 25 items and takes the form of a questionnaire to be completed by a caregiver or other informant sufficiently familiar with the patient. Statistical, clinical and domain-related criteria were used to select items from among a large number of activities of daily living (ADL) questions field tested in pilot studies in the USA, Germany, UK, Russia and Greece. The items included in the B-ADL have been chosen for their sensitivity to cognitive impairment, simplicity of concept, international applicability and their relevance to patients coping with the demands of everyday life. The scale uses items which reflect a wide range of domains. On account of its brevity, it is thought especially suitable for application within a GP and primary care context for both screening a patient's ADL capacities as well as for documentation of treatment effects and the progress of dementia. This paper focuses on a description of the scale and its application.