Objective: To determine the effect of a resistance-training program on walking endurance in a healthy, community-dwelling elderly population. Design: 12-week randomized, controlled trial comparing a resistance-training group with a nonexercising control group. Setting: Hospital-affiliated outpatient exercise facility. Patients: 24 healthy men and women who were 65 years of age or older (mean age +/- SD, 70.4 +/- 4 years; range, 65 to 79 years). Measurements: The primary outcome variable was exhaustive submaximal walking time measured at an intensity of 80% of baseline peak aerobic capacity. Results: Participants in the resistance-training program increased submaximal walking endurance by 9 minutes (from 25 +/- 4 minutes to 34 +/- 9 minutes; P = 0.001), a 38% increase, whereas no change was seen in controls (20 +/- 5 minutes to 19 +/- 10 minutes; P > 0.2; P = 0.005 between groups). The relation between change in leg strength and change in walking endurance was significant (r = 0.48; P = 0.02). Neither group showed a change in peak aerobic capacity or in whole-body composition, although fat-free mass of the leg increased in the exercise group. Conclusions: Resistance training for 3 months improves both leg strength and walking endurance in healthy, community-dwelling elderly persons. This finding is relevant to older persons at risk for disability, because walking endurance and leg strength are important components of physical functioning.