A study on the accuracy of three pedometers: Omron Walking style pro HJ-720IT-E2 (OHJ), Omron walking style II (OII) and Yamax SW-200 (YSW). This study examined the effects of walking speed on the accuracy of the above pedometers: Thirty two subjects (271.22 ± 28,4 months) walked on a treadmill at various speeds (54, 67, 80, 94, and 107 mmin-1) for five min stages. Two investigators determined steps simultaneously by a hand counter and a camera was recording all the trial. YSW and OHJ were measured on the right side and OII was measured on the left side. OHJ and OII did not differ a lot from actual steps at any speed (p>0.05), only YSW differed a lot at 54 m*min-1 (p<0.05). OHJ and OII appeared to be accurate at any speed and YSW provide accurate values at 64 m*min-1 and above.