OBJECTIVES: The increasing number of patients with dementia necessitates the development of rapid and convenient tools to assist with dementia diagnosis. We previously demonstrated the difference in the postural control characteristics during static standing among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and vascular dementia (VaD). In this study, we evaluated the classification accuracy of the postural sway test to assess its capacity to distinguish between types of dementia. DESIGN: A cross-sectional study. SETTING AND PARTICIPANTS: Memory clinic outpatients aged 65-85 years who were clinically diagnosed with AD, DLB, VaD, and cognitively normal (CN) outpatients. METHODS: Static upright standing measurements were conducted under open- and closed-eye conditions to calculate 40 parameters. After variable selection based on statistical significance, 3 dementia classification models (AD vs DLB, AD vs VaD, and DLB vs VaD) based on postural control parameters were created. Bias-corrected accuracy measures using bootstraps were used for assessing the classification performances. RESULTS: The data of 1734 participants (1158 with AD, 105 with DLB, 46 with VaD, and 425 with CN) were analyzed. The area under the curves of receiver operating characteristic curves for AD vs DLB, AD vs VaD, and DLB vs VaD were 0.647 (0.646-0.649), 0.763 (0.761-0.765), and 0.659 (0.656-0.662), respectively. CONCLUSIONS AND IMPLICATIONS: Postural control characteristics differentiated between dementia types with reasonable to good accuracy, especially in the comparison between AD and VaD. Postural control testing may become a valuable assistive tool for dementia diagnosis in the future.