This study describes the availability of physical activity information in the electronic health record, explores how electronic health record documentation correlates with accelerometer-derived physical activity data, and examines whether measured physical activity relates to venous thromboembolism (VTE) prophylaxis use. Prospective observational data comes from community-dwelling older adults admitted to general medicine (n = 65). Spearman correlations were used to examine association of accelerometer-based daily step count with documented walking distance and with duration of VTE prophylaxis. Only 52% of patients had documented walking in nursing and/or physical therapy/occupational therapy notes during the first three hospital days. Median daily steps recorded via accelerometer was 1,370 (interquartile range = 854, 2,387) and correlated poorly with walking distance recorded in physical therapy/occupational therapy notes (median 33 feet/day [interquartile range = 12, 100]; r = .24; p = .27). Activity measures were not associated with use or duration of VTE prophylaxis. VTE prophylaxis use does not appear to be directed by patient activity, for which there is limited documentation.