Peripheral arterial disease (PAD) is associated with high cardiovascular morbidity and mortality. We aimed to examine this relation in a population that tends to be under-represented in research on the topic. In a prospective observational cohort study, residents of 45 nursing homes in Germany were screened for pathological ankle-brachial index (ABI) and observed for five years. Of 1333 participants (median age 84 years), 55.5% had a pathological ABI (≤0.9 or >1.4) on one or both legs. 84.7% of the probands with a low ABI (indicating PAD) had no previously known PAD diagnosis. The five-year mortality was 73.0%. Mortality was higher in individuals with a pathological ABI (76.5%) than in those with a normal ABI (68.7%,p= 0.003). An ABI > 1.4 was associated with a higher mortality (79.4%) than a reduced (74.7%) or normal ABI (68.7%,p= 0.011). Pathological ABI values were associated with an increase in mortality after correction for age, sex and all recorded comorbidities, including cardiac disease. Although PAD is highly prevalent in nursing home residents, it is underdiagnosed and undertreated. In the study cohort, both high and low ABI were important predictors of mortality. PAD deserves more attention in this high-risk population.