Patients with peripheral artery disease (PAD) are at high risk of excess mortality despite major improvements in multimodal pharmacotherapy for cardiovascular disease. However, little is known about co-prevalences and implications for the combination of heart failure (HF) and PAD. Thus, NT-proBNP as a suggested surrogate for HF was evaluated in symptomatic PAD regarding long-term mortality. After approval by the institutional ethics committee a total of 1028 patients with PAD, both with intermittent claudication or critical limb ischemia were included after admission for endovascular repair and were followed up for a median of 4.6 years. Survival information was obtained from central death database queries. During the observation period a total of 336 patients died (calculated annual death rate of 7.1%). NT-proBNP (per one standard deviation increase) was highly associated with outcome in the general cohort in crude (HR 1.86, 95%CI 1.73–2.01) and multivariable-adjusted Cox-regression analyses with all-cause mortality (HR 1.71, 95%CI 1.56–1.89) and CV mortality (HR 1.86, 95% CI 1.55–2.15). Similar HR’s were found in patients with previously documented HF (HR 1.90, 95% CI 1.54–2.38) and without (HR 1.88, 95%CI 1.72–2.05). NT-proBNP levels were independently associated with below-the-knee lesions or multisite target lesions (OR 1.14, 95% CI 1.01–1.30). Our data indicate that increasing NT-proBNP levels are independently associated with long-term mortality in symptomatic PAD patients irrespective of a previously documented HF diagnosis. HF might thus be highly underreported in PAD, especially in patients with the need for below-the-knee revascularization.