Symptoms of intermittent claudication (IC) can be relieved by lifestyle modification, medications, and walking exercises. The intensity of the walking exercise is still debatable. The goal of this study was to determine the effects of accommodating pain-free walking exercise therapy program length on pain-free walking. A descriptive, longitudinal study with repeated measures of exercise capacity was conducted. An IC questionnaire was administered to assess IC signs, symptoms, and lifestyle. Walking was performed on a treadmill for 30 to 50 minutes below the participant's individualized walking pain threshold. The study included patients diagnosed with IC due to peripheral arterial disease. All participants were randomly assigned to three groups. Group A (n = 28) participated in the walking program for 2-9 weeks, group B (n = 30) for 10-14 weeks, and group C (n = 26) for 15-94 weeks. The main outcome measure of the study was to determine changes in exercise capacity: walking distance (miles), walking duration (minutes), and walking speed (mph). Group A increased the amount of distance, duration, and speed walked from pretest to posttest by 80% (P < .001), 27% (P < .001), and 37% (P < .001), respectively. Group B increased the amount of distance, duration, and speed walked from pretest to posttest by 122% (P < .001), 56% (P < .001), and 43% (P < .001), respectively. Group C increased the amount of distance, duration, and speed walked from pretest to posttest by 26% (P = .002), 22% (P = .002), and 5% (P = .541) respectively. We reached the conclusion that a walking program of 10-14 weeks is optimal for achieving the best improvements in walking distance, duration, and speed.