Pedometer step-count accuracy in older adults has tested low and more sensitive pedometers are recommended for this population (Melanson et al., 2004). PURPOSE: Determine Omron BI pedometer accuracy including position invariance in older adults in a controlled setting. METHOD: Twenty-one healthy older adults (10 males, 11 females; M±SD of age, height & weight: 73.57±5.79 yr., 167.85±11.78 cm, 69.06±15.58 kg) wore one of five sets of 10 BI pedometers during testing, one at each of the following 10 positions: left (L) & right (R) Waist (Wst) in the front & back, in front pant Pocket (Pkt) R & L, in L shirt Pkt, around Neck as a pendant, in a Bag on the L, and in a Back Pack (BP), along with two Yamax Digi-Walker SW-200 pedometers on R & L front Waist and a Dynastream AMP 331 activity monitor on R ankle. The participants took 100 straight steps twice (back & forth) with each set of pedometers on a level sidewalk at a natural walking speed. The absolute errors of the step counts (AE = [recorded steps - actual steps]/actual steps * 100) were calculated. Repeated measured ANOVA scrutinized the difference of the pedometer sets and positions by gender. RESULTS: Overall Omron-BI's step counts (100.24±7.98) were accurate for older adults and no difference was found among five sets of pedometers (F = .615, p = .652), which similar to the finding in young adults (Lee, Kim, & Zhu, 2005). A small gender-by-position variation (F = 190, p = .002), however, was noticed. In males, the more accurate positions were back Wst R & L (100.58±1.46, AE = .84% and 100.41±1.54, AE = .78%, respectively), but they were front Wst R & L (100.13±4.94, AE = 1.21% and 100.13±4.94, AE = 1.28%, respectively) in females. The less accurate pedometer positions were Pkt R (103.30±7.51, AE = 4.97%) and Pkt L (104.04±8.54, AE = 6.15%) in males, but neck (90.00±16.91, AE = 5.00%) in females. Omron was found to have a similar accurate rate with AMP 331 monitor (99.57±2.40; AE = 1.15%) and a much better accuracy (AE%: R, Male=.90, Female=1 .21; L, Male=1 .93, Female=1 .42) than Digi-Walkers (AE%: R, Male=8.39, Female = 6.67; L, Male=9.64, Female=10.39) in this study. CONCLUSION: The accuracy of Omron BI pedometer in measuring steps in 10 positions was high in older adults except for the neck position in females. Acknowledgement: Study sponsored by a research grant from Omron Healthcare, Inc.