The performance of 16 patients with Alzheimer's disease (AD) was compared to 11 patients with right-frontotemporal dementia (FTD) and 11 patients with left-FTD on a comprehensive neuropsychological battery. Standardized scores (i.e., z scores based on normal control data) were analyzed for 5 cognitive domains. The results revealed that the AD group displayed significant impairment in visual-constructional ability relative to the two FTD groups; however, no significant difference was found between the groups on memory scores (verbal and nonverbal). Patients with left-FTD scored significantly below patients with AD on the language measures (e.g., word retrieval, verbal semantic memory), and verbal executive ability (phonemic fluency); AD patients did not differ from patients with right-FTD on these measures. Patients with right-FTD exhibited significantly more perseverative behavior than AD patients; AD patients did not differ from left-FTD patients on this parameter. These results indicate that the pattern of neuropsychological performance of AD patients is distinguishable from patients with left and right frontal frontotemporal dementia.