A child's natural gait pattern may be affected by the gait laboratory environment. Wearable devices using body-worn sensors have been developed for gait analysis. The purpose of this study was to validate and explore the use of foot-worn inertial sensors for the measurement of selected spatio-temporal parameters, based on the 3D foot trajectory, in independently walking children with cerebral palsy (CP). We performed a case control study with 14 children with CP aged 6-15 years old and 15 age-matched controls. Accuracy and precision of the foot-worn device were measured using an optical motion capture system as the reference system. Mean accuracy +/- precision for both groups was 3.4 +/- 4.6 cm for stride length, 4.3 +/- 4.2 cm/s for speed and 0.5 +/- 2.9 degrees for strike angle. Longer stance and shorter swing phases with an increase in double support were observed in children with CP (p = 0.001). Stride length, speed and peak angular velocity during swing were decreased in paretic limbs, with significant differences in strike and liftoff angles. Children with cerebral palsy showed significantly higher inter-stride variability (measured by their coefficient of variation) for speed, stride length, swing and stance. During turning trajectories speed and stride length decreased significantly (p < 0.01) for both groups, whereas stance increased significantly (p < 0.01) in CP children only. Foot-worn inertial sensors allowed us to analyze gait spatiotemporal data outside a laboratory environment with good accuracy and precision and congruent results with what is known of gait variations during linear walking in children with CP. (C) 2013 Elsevier B. V. All rights reserved.