Background Lower extremity peripheral artery disease is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. This study provides the fi rst comparison of the prevalence of peripheral artery disease between high-income countries (HIC) and low-income or middle-income countries (LMIC), establishes the primary risk factors for peripheral artery disease in these settings, and estimates the number of people living with peripheral artery disease regionally and globally. Methods We did a systematic review of the literature on the prevalence of peripheral artery disease in which we searched for community-based studies since 1997 that defi ned peripheral artery disease as an ankle brachial index (ABI) lower than or equal to 0.90. We used epidemiological modelling to defi ne age-specifi c and sex-specifi c prevalence rates in HIC and in LMIC and combined them with UN population numbers for 2000 and 2010 to estimate the global prevalence of peripheral artery disease. Within a subset of studies, we did meta-analyses of odds ratios (ORs) associated with 15 putative risk factors for peripheral artery disease to estimate their eff ect size in HIC and LMIC. We then used the risk factors to predict peripheral artery disease numbers in eight WHO regions (three HIC and fi ve LMIC). Findings 34 studies satisfi ed the inclusion criteria, 22 from HIC and 12 from LMIC, including 112 027 participants, of which 9347 had peripheral artery disease. Sex-specifi c prevalence rates increased with age and were broadly similar in HIC and LMIC and in men and women. The prevalence in HIC at age 45-49 years was 5.28% (95% CI 3.38-8.17%) in women and 5.41% (3.41-8.49%) in men, and at age 85-89 years, it was 18.38% (11.16-28.76%) in women and 18.83% (12.03-28.25%) in men. Prevalence in men was lower in LMIC than in HIC (2.89% [2.04-4.07%] at 45-49 years and 14.94% [9.58-22.56%] at 85-89 years). In LMIC, rates were higher in women than in men, especially at younger ages (6.31% [4.86-8.15%] of women aged 45-49 years). Smoking was an important risk factor in both HIC and LMIC, with meta-OR for current smoking of 2.72 (95% CI 2.39-3.09) in HIC and 1.42 (1.25-1.62) in LMIC, followed by diabetes (1.88 [1.66-2.14] vs 1.47 [1.29-1.68]), hypertension (1.55 [1.42-1.71] vs 1.36 [1.24-1.50]), and hypercholesterolaemia (1.19 [1.07-1.33] vs 1.14 [1.03-1.25]). Globally, 202 million people were living with peripheral artery disease in 2010, 69.7% of them in LMIC, including 54.8 million in southeast Asia and 45.9 million in the western Pacifi c Region. During the preceding decade the number of individuals with peripheral artery disease increased by 28.7% in LMIC and 13.1% in HIC. Interpretation In the 21st century, peripheral artery disease has become a global problem. Governments, nongovernmental organisations, and the private sector in LMIC need to address the social and economic consequences, and assess the best strategies for optimum treatment and prevention of this disease.