To compare spatial and temporal measures during lead limb obstacle crossing between subjects with stroke and healthy subjects.Experimental, observational, with matched controls.Geriatric rehabilitation unit in a tertiary referral hospital.Distance data were available for 19 subjects with stroke and 19 able-bodied subjects. Temporal data were available for 16 subjects with stroke and 16 able-bodied subjects. Subjects with stroke were inpatients and had to be able to walk 10 meters without assistance or gait aid.Subjects were required to step over high and wide obstacles, ranging from 1 to 8cm, and trials were videotaped.Toe clearance, preobstacle distance, postobstacle distance, step length, proportion of step length preobstacle, step time, preobstacle step time, postobstacle step time, and proportion of step time preobstacle were measured.Mann-Whitney U tests were performed to determine differences between the 2 groups. Subjects with stroke had significantly higher toe clearance, smaller postobstacle distances, and greater step times than healthy subjects. Subjects with stroke did not demonstrate a significant reduction in preobstacle distance.By modifying their lead limb trajectory during obstacle crossing, persons with stroke reduce the risk of a trip due to toe contact, but the modification may expose them to other safety risks.