Background: Diabetes mellitus (DM) is an established risk factor for intermittent claudication (IC) and other manifestations of atherosclerotic peripheral arterial disease. Indications for surgery in infrainguinal IC are debated, and there are conflicting reports regarding its outcomes in patients with DM. Aims of this study were to compare both short- and long-term effects on total- and cardiovascular (CV) mortality, major adverse cardiovascular events (MACEs), acute myocardial infarction (AMI), stroke, and major amputation following infrainguinal endovascular surgery for IC in patients with and without DM. We also evaluated potential relationships between diabetic control and outcomes in patients with DM. Methods: Nationwide observational cohort study of patients registered in the Swedish Vascular Registry and the Swedish National Diabetes Registry. Propensity score adjusted comparison of total and CV mortality, MACE, AMI, stroke, and major amputation after elective infrainguinal endovascular surgery for IC in 626 patients with and 1112 without DM at 30 postoperative days and after median 5.2 [interquartile range (IQR) 4.2–6.3] years of follow-up for patients with DM, and 5.4 (IQR 4.3–6.5) years for those without. Results: In propensity score adjusted Cox regression after 30 postoperative days, there were no differences between groups in morbidity or mortality. At last follow-up, patients with DM showed higher rates of MACE [hazard ratio (HR) 1.26, confidence interval (CI) 1.07–1.48; p < 0.01], AMI (HR 1.48, CI 1.09–2.00; p = 0.01), and major amputation (HR 2.31, CI 1.24–4.32; p < 0.01). Among patients with DM, higher HbA1c was associated with higher total mortality during follow-up (HR 1.01, CI 1.00–1.03; p = 0.045). Conclusion: Patients with DM have higher rates of MACE, AMI, and major amputation in propensity score adjusted analysis during 5 years of follow-up after infrainguinal endovascular surgery for IC. Furthermore, HbA1c is associated with total mortality in patients with DM. Prevention and treatment of DM is important to improve cardiovascular and limb outcomes.