Accelerometers and pedometers have been used to monitor the number of steps. However, the evidence on the step‐counting accuracy of these devices – especially accelerometers – is limited in persons with Down syndrome (DS). This study therefore examined the accuracy of accelerometers placed on the hip or wrist and of a pedometer with a uni‐axial accelerometer mechanism in measuring steps in persons with DS and whether device error is associated with walking speed, height, weight, body mass index, waist circumference, leg length, age or sex.. To read the full article, log in using your MPFT NHS OpenAthens details.