Objectives: Among persons with lower extremity peripheral artery disease (PAD), we determined whether objective measures of walking performance predict mortality independently of the ankle brachial index (ABI). Background: The ability of office-based functional performance measures to predict mortality in patients with PAD is unknown. Methods: Participants were 444 persons with PAD followed prospectively for 4.8 years. The 6-min walk and 4-m walks at usual and fastest pace were measured at baseline. Cox proportional hazard models were used to assess relations between baseline measures of lower extremity performance with mortality, adjusting for confounders. Results: One hundred twenty-seven patients (28.6%) died during follow-up. Adjusting for age, gender, race, comorbidities, ABI, and other confounders, participants in the poorest baseline quartile of 6-min walk performance had significantly increased total mortality (hazard ratio [HR] 2.36 [95% confidence interval (CI) 1.33 to 4.18]) and cardiovascular mortality (HR 5.59 [95% CI 1.97 to 15.9]) compared with the best quartile of baseline performance. Participants in the poorest baseline quartile of normal-paced 4-m walking speed had significantly increased total mortality (HR 1.86 [95% CI 1.06 to 3.29]) and cardiovascular mortality (HR 2.55 [95% CI 1.01 to 6.46]) compared with the best quartile of baseline performance. Conclusions: This study demonstrates for the first time that performance-based measures, which can be administered in an office setting, provide prognostic information regarding mortality in persons with PAD beyond that provided by the ABI.