The objective of this study is to determine the prevalence of cognitive impairment (CogI) in patients hospitalized for congestive heart failure, and the influence of CogI on mortality and hospital readmission. This is a multicenter cohort study of patients hospitalized for congestive heart failure enrolled in the RICA registry. The patients were divided into 3 groups according to their Short Portable Mental Status Questionnaire score: 0–3 errors (no CogI or mild CogI), 4–7 (moderate CogI) and 8–10 (severe CogI). A total of 3845 patients with a mean (SD) age of 79 (8.6) years were included; 2038 (53%) were women. A total of 550 (14%) patients had moderate CogI and 76 (2%) had severe CogI. Factors independently associated with severe CogI were age (OR 1.09, 95% CI 1.05–1.14 p  < 0.001), male sex (OR 0.57, 95% CI 0.34–0.95, p  = 0.031), heart rate (OR 1.01, 95% CI 1.00–1.02, p  = 0.004), Charlson index (OR 1.16, 95% CI 1.06–1.27, p  = 0.002), and history of stroke (OR 2.67, 95% CI 1.60–4.44, p  < 0.001). Severe CogI was associated with higher mortality after one year (HR 3.05, 95% CI 2.25–4.14, p  < 0.001). The composite variable of death/hospital readmission was higher in patients with CogI (log rank p  < 0.001). Patients with heart failure and severe CogI are older and have a higher comorbidity burden, lower survival, and a higher rate of death or readmission at 1 year, compared to patients with no CogI.