Although memory deficits are typically the earliest and most profound symptoms of Alzheimer's disease (AD) and mild cognitive impairment (MCI), there is increasing recognition of subtle executive dysfunctions in these patients. The purpose of the present study was to determine the sensitivity of the Behavioral Assessment of the Dysexecutive Syndrome (BADS), and to detect early specific signs of the dysexecutive syndrome in the transition from normal cognition to dementia. The BADS was administered to 50 MCI subjects, 50 mild AD patients, and 50 normal controls. Statistically significant differences were found among the three groups with the AD patients performing most poorly, and the MCI subjects performing between controls and AD patients. The Rule Shift Cards and the Action Program subtests were the most highly discriminative between MCI and controls; the Zoo Map and Modified Six Elements between MCI and AD; and the Action Program, Zoo Map, and Modified Six Elements between AD and controls. These results demonstrate that the BADS is clinically useful in discriminating between normal cognition and progressive neurodegenerative conditions. Furthermore, these data confirm the presence of a dysexecutive syndrome even in mildly impaired elderly subjects.