Vascular function, as measured by flow mediated dilation (FMD) and nitroglycerin mediated dilation (NMD), is impaired in COPD. Increases in systemic inflammatory mediators during acute exacerbations of COPD (AECOPD) may further impair vascular function and may account for the increased prevalence of cardiovascular disease in COPD patients. Similarly it may account for the increased morbidity and mortality in COPD patients hospitalized with acute exacerbations. We hypothesized that FMD and NMD would be impaired during AECOPD requiring hospitalization and that vascular function would improve upon AECOPD resolution. We used FMD and NMD to evaluate vascular function in 19 patients hospitalized with AECOPD. FMD and NMD were repeated approximately three months later in 8 of these patients. In these eight patients significant improvements were observed in FMD (2.6 ± 1.5% vs 5.1 ± 2.4%, p = 0.04) and NMD (5.0 ± 2.6% vs 13.3 ± 4.5, p = 0.02) after resolution of their exacerbation. We conclude that endothelial and vascular smooth muscle function is markedly impaired during AECOPD requiring hospitalization and improves following resolution. The systemic vascular impairment that occurs during AECOPD may partially explain the observed increased in cardiac morbidity and mortality that occur in this population.