Objectives: To investigate the prevalence and classification of potentially reversible conditions in a prospective memory clinic cohort of younger and elderly patients with cognitive symptoms. Patients: 1000 consecutive patients referred during a period of 54 months to a university hospital multidisciplinary memory clinic based in neurology. Methods: All patients were referred for diagnostic evaluation and treatment of cognitive symptoms. The multidisciplinary staff prospectively established a standardised consensus report for each patient based on the results of clinical and ancillary investigations with classification of cognitive profile, primary underlying cause, and concomitant conditions. Results: The mean age of the patients was 66.1 years (range 17-98) and 43% met diagnostic criteria for dementia. A potentially reversible primary aetiology for cognitive symptoms was identified in 19% and a potentially reversible concomitant condition in 23% of all patients. In the subgroup of patients with dementia, 4% had a potentially reversible primary aetiology. Careful clinical examination, routine laboratory tests, and cranial computed tomography identified most of these conditions. Conclusions: Reversible conditions are most often encountered in patients with mild cognitive disturbances. Although treatment may not always result in full reversal of cognitive symptoms, potentially reversible conditions should be identified in the diagnostic evaluation of the patient.