This study aims to determine the length of the gait initiation phase before achieving steady state walking in frail older people. Based on body fixed sensors, habitual walking was analysed in 116 community-dwelling older persons (mean age 83.1 years, 84% women). The start of steady state walking was identified using an algorithm taking into account speeds from consecutive strides. On average, participants reached a walking speed of 0.66 m/s after an acceleration phase of 1.43 m (89% after 2.47 m). When spatio-temporal variables were calculated from 4, 6, 8, 10, or 20 consecutive stride cycles after achieving steady state, similar values were observed for mean gait speed and stride length. The variability of these factors differed depending on the number of gait cycles. Assessments of steady state gait in frail elderly people should therefore exclude the first 2.5m of walking. If gait variability is to be assessed, it is recommended that more than 20 stride cycles be used.