Objective To investigate the psychometric properties of the Brief Fatigue Inventory (BFI) in community-dwelling older adults. Design Cross-sectional validation study. Setting Community based. Participants Subjects (N=302) were nondemented older adults (mean age, 76.44y; 54% women). Interventions Not applicable. Main Outcome Measures BFI total, severity, and interference summation scores. Results A principal component analysis (PCA) yielded 2 factors, fatigue severity and interference, explaining 65.94% of the variance. Both factors had good reliability, with Cronbach alpha values of .867 for fatigue interference and .818 for fatigue severity. Higher fatigue scores were associated with older age and worse physical and cognitive functions. Conclusions Fatigue is a common and debilitating symptom in the aging population. The current study provides novel findings in validating and establishing a bidimensional factor structure for the BFI in older adults. Severity and interference were differentially related to important health outcomes; therefore, using these subscales in addition to the total BFI score is recommended with older adults. Because of its relatively short administration time and established psychometric properties, the BFI can be successfully incorporated into longitudinal studies and clinical trials.