Gait disorders in people with dementia have been documented in a number of studies. There is some preliminary evidence suggesting there may be a relationship between dementia type and gait abnormality. Quantitative gait analysis has not previously been reported for people diagnosed with dementia with Lewy bodies (DLB). Therefore, this study aimed to quantify gait patterns of people with DLB and compare them with those of people with Alzheimer's disease (AD) and control subjects. Two groups of 10 subjects divided according to a diagnosis of DLB and AD, and 10 control subjects underwent gait analysis using an electronic walkway. Participants were required to walk at self-selected slow, preferred and fast speeds. There were no differences between the DLB and AD patient groups for any of the measured gait variables. Velocity and stride length values were significantly reduced in both patient groups compared to the control group at all speeds and percentage of time spent in double limb support was significantly increased in both patient groups compared to the control group at all walking speeds. Significant correlations were found between gait speeds and gait outcome variables. Spatiotemporal gait characteristics of people with AD and DLB are similar, but significantly different from the normal population.