Previous studies have shown there is a relationship between sleep and mobility in older adults by collecting and analysing self-reported data from surveys and questionnaires, or by using objective measures from polysomnography or actigraphy. However, these methods have limitations for long-term monitoring, especially for community-dwelling adults. In this paper, we investigate the association between sleep and indoor mobility using longitudinal data collected over a period of about 12 months for older adults (65 years or older) living at home in Australia. The data was collected objectively and continuously using non-invasive and passive sensors. First, we explored whether sleep and indoor mobility are different across gender and age groups (70s, 80s, and 90s). Second, we investigate the association of sleep and next-day indoor mobility through a stepwise multivariate regression. We found that males and females have significant differences in mobility, time in bed, total time in sleep, number and duration of awakenings and sleep efficiency. Additionally, mobility and all sleep measures significantly vary across the three age groups, except for sleep onset latency between 80s and 90s. Our findings show that sleep efficiency and total sleep time are the key sleep measures affecting next-day mobility, while sleep onset latency has the least effect.Clinical relevance - Our study contributes to a better understanding of the sleep patterns of older adults and how they affect their physical functioning.