CERAD-NAB (Consortium to Establish a Registry for Alzheimer's Disease-Neuropsychological Assessment Battery) data were compared between 51 patients with frontotemporal dementia, 13 with semantic dementia, and 69 with Alzheimer's disease. There were statistically significant differences between the 3 groups. Compared with patients with Alzheimer's disease, patients with frontotemporal dementia were more impaired on Animal Fluency but not on any other CERAD-NAB subtest. Patients with semantic dementia performed worse in Animal Fluency and Boston Naming Test compared with frontotemporal dementia and Alzheimer's disease. Multiple logistic regression analysis revealed that in the differentiation between frontotemporal dementia and Alzheimer's disease, the combination of Animal Fluency and Boston Naming Test correctly classified 90.5% of patients. In segregating semantic dementia and Alzheimer's disease, the combination of Boston Naming Test and Mini Mental State Examination resulted in a correct classification of 96.3%. These findings demonstrate that the Mini Mental State Examination and the language subtests of the CERAD-NAB are valuable clinical instruments for the differential diagnosis between early frontotemporal dementia, semantic dementia, and Alzheimer's disease.