STUDY DESIGN Repeated measures of 14 temporal factors of gait obtained with a multimemory stopwatch from a variety of subjects with locomotor impairments. OBJECTIVES To estimate the intratester and intertester reliability of 14 temporal factors of gait by using a multimemory stopwatch; to compare novice and expert clinicians at mastery of making these temporal measurements. BACKGROUND Temporal gait measures are useful for describing the effectiveness of treatment interventions in patients with locomotor impairments. METHODS AND MEASURES Eleven adult subjects (mean age, 48.4 years; SD, 5.7 years), 10 with locomotor impairments and 1 elderly adult, ambulated along a 6-m walkway 3 times at a self-selected walking speed. The subjects were videotaped from the side as they walked. Four physical therapists independently analyzed the videotapes on 2 occasions; 2 examiners were recent graduates, and 2 others had 23 years of clinical experience. Intraclass correlation coefficients were used to estimate intratester reliability. A component of variance analysis quantified the sources of variation. RESULTS Intraclass correlation coefficients for each of the 14 variables varied from 0.88 to 0.98. The major contributor to variance was subject, followed by trial, error, and tester; the tester factor generally contributed less than 1% to the total variance. CONCLUSIONS Reliable measurements of the temporal aspects of gait can be made by using a multimemory stopwatch and videotape in a clinical setting on patients with various locomotor problems. Our data suggest that measurements obtained by more experienced physical therapists were no more reliable than those made by recent graduates.