Abstract Background Anemia is common in cardio-renal syndrome and may contribute to increase mortality. Objective To examine the prevalence of anemia and its relationship with cardio-renal syndrome, and to evaluate the risk factors for death. Methods Retrospective study with all patients admitted with congestive heart failure (CHF). The parameters as age, gender, hemoglobin (Hb), estimated glomerular filtration rate (eGFR), New York Heart Association (NYHA) functional class, ejection fraction (EF%), hospital stay, hypertension, diabetes, smoking and CHF etiology were analyzed. Anemia was defined as Hb < 12g/dL, systolic dysfunction EF < 55% and renal failure was stratified according to K-DOQI classification. Statistical analysis was done by the programs EpiInfo and SPSS for windows. Results A total of 174 patients were studied. The average age was 63 ± 16 years, 65.5% were males, and 18 of them (11%) were non-survivors. Anemia was observed in 45% of patients, and 82% presented some degree of renal failure. The majority of patients (87%) were classified as NYHA functional class III or IV. The average ejection fraction was 43.9 ± 16.6%, and there was no difference between survivors and non-survivors ( p > 0.05). Mortality was not significantly higher among patients with anemia (12.4%) when comparing to those without anemia (8.3%, p = 0.31). There was a progressive decrease in the level of hemoglobin as renal function decreased ( p < 0.05). Increased serum creatinine was a significant risk factor for death (OR = 1.59, 95% CI = 1.074–2.363, p = 0.021), and increased EF% was a protection factor against development of death (OR = 0.904, 95% CI = 0.845–0.973, p = 0.007). Conclusions The prevalence of anemia is high among patients with cardio-renal syndrome but was not associated with increased mortality. Increased serum creatinine and low EF% were variables associated with death.