BACKGROUND: Systolic heart failure (SHF) and chronic obstructive pulmonary disease (COPD) are frequently associated. The purpose of our study was to explore the impact of COPD severity on symptoms and prognosis in patients with SHF. METHODS AND RESULTS: Chronic obstructive pulmonary disease was systematically screened by spirometry in 348 patients admitted for SHF from April 2002 to December 2006. Severity of COPD was defined according to the GOLD classification. Prevalence of COPD was 37.9 %. Patients' distribution according to GOLD stages I, II, II and IV were, respectively, 51.5, 37.9, 7.6 and 3.0 %. Severity of dyspnoea increases with GOLD stage. There was a significant correlation between NYHA stage and left ventricular ejection fraction in patients without COPD (R (2) = 0.03; P = 0.01) but not in patients with COPD. Mean follow-up was of 54.9 ± 27.4 months. Mortality was 46.6 % and was highest in the COPD group (53.8 vs. 42.3 %; P = 0.049). Kaplan-Meier survival curves showed that patients with GOLD stage I had the same prognosis than patients without COPD and mortality increased from GOLD stage II to stage IV. After multivariate analysis, GOLD stage and diuretics' dose were independently associated with mortality. CONCLUSIONS: Chronic obstructive pulmonary disease is frequent in patients with SHF and increases mortality. Since dyspnoea is poorly specific of COPD in chronic heart failure patients, COPD remains underdiagnosed thus leading to inappropriate increase of diuretics' dose. COPD should be systematically screened in patients with SHF to adapt prescription of selective β1-blockers, and diuretics' dose and reduce the exposition to risk factors.