Background: Smartphone apps provide novel ways for triggering lifestyle change by coupling objective measurements of health behavior with tailored feedback. Little is known about end-user preferences regarding the content of mobile health (mHealth) interventions. The aim of this study was to assess smartphone use and preferences regarding app content among intermittent claudication patients and their treating physical therapists. Methods: A cross-sectional survey was sent via an internal email system to 1,514 physical therapists specialized in treating patients with intermittent claudication. They were asked to complete one questionnaire themselves and administer a second to their intermittent claudication patients currently under treatment. Data on participant characteristics and smartphone use were collected from all respondents. The preferred app components were obtained from participants owning a smartphone. Binary logistic regression analysis was used to explore the adjusted association between age and attained educational level, and smartphone use. Results: The response rate of therapists was 40.8% (617/1,514), and a total of 488 patients completed the survey. After excluding incomplete forms, a total of 615 physical therapist forms and 483 patient forms were analyzed. Overall, 40.6% of patients and 95% of therapists owned a smartphone. Higher educational level was associated with smartphone ownership (adjusted odds ratio = 2.46, 95% confidence interval (CI) = 1.41-4.27, P = 0.001). Compared to patients aged >= 75 years, lower age was associated with higher odds of owning a smartphone (adjusted odds ratios for patients aged <= 54 years = 21.27, 95% CI = 6.82-66.30, P < 0.001; aged 55-64 years = 4.76, 95% CI = 2.52-9.00, P < 0.001; and aged 65-74 years = 2.58, 95% CI = 1.54-4.33, P < 0.001). The most preferred app components for intermittent claudication patients in possession of a smartphone included monitoring treadmill-measured walking distances (71%), global positioning system tracking of walks (50%), and daily physical activity monitoring (49%). Physical therapists were most interested in global positioning system tracking of walks (89%), daily physical activity monitoring (82%), keeping track of treadmill-measured walking distance (79%), help with smoking cessation (65%). Conclusions: Smartphone ownership is associated with younger age and a higher educational level in patients with intermittent claudication. This study provides a framework of end-user preferences regarding desired features to guide the development of an app to potentiate health outcomes of intermittent claudication treatment.