This study of subjects with multiple sclerosis or hemiparesis assessed the interrater and test-retest reliability of temporal-distance (TD) gait measures and examined the relationship of TD values to functional ambulation ability. Sixty-one subjects ambulated twice on a 9-m (30-ft) paper walkway and rested 15 minutes between trials. An ink footprint record and ambulation time were used to calculate velocity, cadence, step and stride lengths, stride length to lower extremity length ratio, and step- and stride-time differentials. Subjects were rated on a scale that assessed the amount of manual assistance required for ambulation. Interrater and test-retest reliability were high for all TD measures except stride-time differential for the total sample and within diagnostic categories. The TD values were highly reliable in all functional categories except one. All TD measures except stride- and step-time differential displayed a strong linear relationship to the functional ambulation category. Implications for using TD measures in clinical settings are discussed.