Anemia in heart failure (HF) is increasingly recognized and treated, but little is known about the prevalence and its relation to outcomes in patients hospitalized for decompensated HF in a situation of both reduced and preserved systolic function. We hypothesized that lower hemoglobin is correlated with death during hospitalization and 60 to 90 days postdischarge in patients with HF. The Organized Program to Initiate Lifesaving Treatment in Patients with Heart Failure is a registry and performance improvement program for hospitalized patients with HF. Study cohorts were defined by admission hemoglobin quartile. Data from 48,612 patients at 259 hospitals showed that half of the total cohort had low hemoglobin (<12.1 g/dl) and that 25% were moderately to severely anemic (lowest hemoglobin quartile, 5 to 10.7 g/dl). Patients with low hemoglobin were older, were more often women and Caucasian, and had preserved systolic function and elevated creatinine. They were also less likely to receive angiotensin-converting enzyme inhibitors and β blockers at discharge. Anemic patients had higher in-hospital mortality (4.8% vs 3.0%, lowest vs highest quartile), longer hospital length of stay (6.5 vs 5.3 days), and more readmissions by 90 days (33.1% vs 24.2%) (all p <0.0001). In conclusion, these data reveal a higher prevalence of low hemoglobin in hospitalized patients than noted in randomized HF trials and outpatient registries. Lower hemoglobin is associated with higher morbidity and mortality in hospitalized patients with HF.