Objectives: To quantify, using accelerometry, walking activity of older rehabilitation inpatients and to examine the relationship between walking activity and functional outcomes. Design: Prospective cohort study. Setting: Inpatient geriatric rehabilitation unit. Participants: Of 74 consecutive eligible patients, aged 60 years or older and able to walk independently or with assistance, 60 participants (32 males, 28 females) with a mean (SD) length of stay of 37 (26) days completed the study. Intervention Measures: An accelerometer was worn in daytime hours from study recruitment until discharge to monitor daily walking minutes. Results: On study entry, patients spent a median (IQR) of 33 (20 to 48) minutes (7%) of the daily monitored eight hour period walking. By discharge, this had increased to 43 (30 to 56) minutes (9%) (p< 0.001). Average daily walking activity over the week prior to discharge correlated with change in gait speed from admission to discharge (p<0.05). Walking activity prior to discharge was significantly different (p<0.05) between the slowest gait speed group (=0.4 m/s) and the fastest gait speed group (=0.8 m/s). Those with discharge gait speeds =0.8 m/s (associated with ability to be ambulant in the community) had median (IQR) daily walking times at discharge of 51 (33 to 78) minutes. Conclusion: Activity monitoring has the potential to assist clinicians and patients set goals around activity levels to achieve better outcomes.