BACKGROUND: Falls are common in people with Alzheimer's disease (AD). There is some evidence that deficits in vision, peripheral sensation, strength, reaction time and balance may be partly responsible for this increased risk. AIMS: To determine the feasibility and test-retest reliability of a physiological test battery designed to assess falls risk [the Physiological Profile Assessment (PPA)] in people with AD, and to compare their PPA scores to age- and sex-matched controls. METHODS: Twenty-one community-dwelling people with probable, mild to moderate AD aged 63-91 years, and 21 age- and sex-matched controls underwent the PPA tests and the Mini-Mental State Examination. All tests were then repeated in the AD group to determine test-retest reliability. RESULTS: Most of the PPA tests could be successfully administered to participants with AD. The AD group had a significantly higher overall falls risk score (t(40) = -2.41, p < 0.02), slower hand (t(40) = -4.86, p < 0.01) and foot reaction time (t(40) = -2.26, p < 0.05) and worse coordinated stability (t(40) = -2.40, p < 0.05) than the controls. CONCLUSION: Physiological falls risk assessment is feasible in older people with mild to moderate AD. Older people with AD demonstrate significant impairments in several physiological domains, particularly reaction time, compared to controls.