This study in male patients with intermittent claudication and age- and diabetes-matched controls showed an association of l-homoarginine and l-arginine with PAD. During follow-up, l-arginine was associated with incident cardiovascular events probably due to its primary role in NO metabolism and impact on endothelial integrity. l-homoarginine was related to all-cause mortality implying a broader role in metabolic processes besides endothelial function.