OBJECTIVES: To compare the test-retest reliability and validity of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function (PF) subscale and the Lower Extremity Functional Scale (LEFS) in community-dwelling adults with hip osteoarthritis (OA). STUDY DESIGN AND SETTING: One hundred adults with symptomatic hip OA participated in the study. Test-retest reliability was assessed by administering the WOMAC and LEFS at participants' initial visits and after 1 week. Discriminant validity from pain measures was assessed by examining the WOMAC-PF and the LEFS correlations with the PF and bodily pain subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Convergent validity was assessed by comparing correlations between the WOMAC-PF and LEFS with the gait speed test, step test, and timed stair tests. Intraclass correlation coefficients (ICCs), standard error of measurement, and Pearson correlation coefficients were calculated. RESULT: ICC estimates of 0.90 and 0.92 were obtained for the WOMAC-PF and LEFS, respectively. The minimal detectable change scores were 9.1 WOMAC-PF and 9.9 LEFS points. Discriminant validity was evident for the LEFS but not for the WOMAC-PF. The WOMAC-PF and LEFS showed similar levels of convergent validity; however, WOMAC-PF and gait speed showed a relatively low correlation. CONCLUSION: The LEFS has good measurement properties--namely test-retest reliability and cross-sectional construct validity--and it could be an alternative to WOMAC-PF.