Background: Chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) frequently coexist but concurrent COPD+CHF has been little investigated. Design: This multicentre survey (SUSPIRIUM) was designed to evaluate: the prevalence of COPD in stable CHF and CHF in stable COPD; diagnostic/therapeutic work-up for concurrent COPD +CHF; clinical profile of patients with COPD+CHF; predictors of COPD in CHF and CHF in COPD. Methods: A 5-month-long cross-sectional prospective observational survey was conducted in 10 cardiac and 10 respiratory connected outpatient units. Results: The prevalence of CHF in the 378 surveyed COPD patients was 11.9% (95% confidence interval 8.8-16.6) and the prevalence of COPD in 375 CHF patients was 31.5% (95% confidence interval 26.8-36.4). Diagnostic tests for suspected comorbidity were prescribed in 21.6% and 22.9% of COPD and CHF patients, respectively. Patients with coexisting CHF+COPD had a higher incidence of hypertension, physical inactivity and more frequently a GOLD score of 3 or greater. Compared to CHF only, CHF+COPD patients were significantly older, more frequently smokers, at worse respiratory risk and in a higher New York Heart Association class. Conversely, hypercholesterolaemia, a family history of ischaemic heart disease, fluid retention and comorbidities were more frequent in COPD+CHF than COPD-only patients. At multivariate analysis, a GOLD score of 3 or greater in CHF strongly predicted coexistent COPD (odds ratio 8.985, P < 0.0001) as did a history of other respiratory diseases (5.184, P < 0.0001). A history of ischaemic heart disease (4.868, P < 0.0001), atrial fibrillation (3.302, P < 0.0001) and sedentary lifestyle (2.814, P < 0.004) predicted coexistent CHF in COPD. Conclusion: The high prevalence of COPD+CHF calls for integrated disease management between cardiologists and pulmonologists. SUSPIRIUM identifies which cardiac/pulmonary outpatients should be screened for the respective comorbidity.