Sedentary behaviour (SB) independently affects health status (Healy et al., 2008) and is prevalent in older adults (10.27±0.80 hours/24 hours-1, vs. young adults: 9.48±0.70 hours/24 hours-1) (Craig et al, 2009). However, the patterns of SB and Physical activity (PA) accumulations have not been described. The present study aimed to examine the patterns of SB and PA accumulation in a population of free-living older adults, classifying groups by mobility patterns. A triaxial GENEActiv accelerometer (ActivInsights, Kimbolton UK) was mounted anteriorly at 50% of femur length using 2 Tegaderm patches (3M Health Care, USA). Participants (n=90, age: 73.72±6.28 years, 48 females) completed 7 days of habitual mobility before returning the accelerometer. The Cheshire Algorithm of Sedentarism (Wullems et al, 2015) was used to analyse the raw data. Participants were then grouped into Sedentary (n=65, 37 female) (SB: ≥8 hours/4 hours-1, ≥150 min of Continuous MVPA (cMVPA): <150 mins/7 days-1), Ambulator (n=11, 6 female) (SB: <8 hours/24 hours-1, cMVPA: <150 mins/7 days-1), Active Couch Potato (ACP) (n=13, 5 female) (SB: ≥8 hours/24 hours-1, cMVPA: ≥150 mins/7 days-1), or Active Ambulator, 0 female) (SB: <8 hours/24 hours-1, cMVPA: ≥150 mins/7 days-1). The single Active Ambulator participant was removed from between group comparison due to small group size. Results are presented as Mean ± Standard Deviation, p = 0.05, with groups compared by Kruskall-Wallis and Mann Whitney-U (post hoc). Ambulators accumulated the least amount of SB (Figure 1). Number of SB breaks per 24 hours (2mins of PA following ≥1min SB) was similar between groups (Sedentary: 22.0±5.62, Ambulator: 22.44±4.73, ACP: 22.36±6.32). However, Ambulators accumulated 50% of their SB time (W50%) through shorter bouts (39.16±13.33 mins/24 hours-1, Sedentary: 58.53±22.86 mins/24 hours-1, ACP: 49.32±20.54 mins/24 hours-1). This was due to Ambulators accumulating more Standing, Light Intensity Physical Activity (LIPA), and <10 min Continuous MVPA (sMVPA) than ACP and Sedentary populations (Figure 1). The ACP population accumulated more cMVPA than Ambulator and Sedentary populations (Figure 1) by performing more frequent cMVPA bouts per 24 hours (2.04±1.93, Ambulator: 0.42±0.78, Sedentary: 0.39± 0.80). The results suggest that older adults use different patterns of SB/PA. Thus, 1%, 12%, 14% and 72% of the study population could be categorised as Active Ambulator, Ambulator, ACP and Sedentary respectively. Those who have shorter SB bouts and accumulate the least amount of SB appear to substitute this time with Standing, LIPA and sMVPA as opposed to cMVPA. Using only SB breaks as a measure of SB patterns maybe insufficient to highlight differences between older adults. Future research should aim to examine how these multiple SB/PA patterns affect health status.