Anemia is a common finding in elderly individuals. Several studies have shown a strong relationship between anemia, morbidity and mortality, suggesting anemia as a significant independent predictor of adverse outcome in elderly hospitalized patients. The pathophisiology of anemia in the elderly is not yet completely understood. Several mechanisms are involved. We investigated the prevalence of anemia in a cohort of 193 elderly patients admitted to the Internal Medicine Ward of Ca'Granda Policlinico Hospital along 6 months, and its relationship to comorbidities and to the length of hospitalization. Anemia was classified according to the WHO criteria. The majority of patients (48 %) had a mildmoderate, normocytic anemia; severe anemia was found in 8 out of 92 anemic patients. In a subgroup of patients erythropoietin was tested and resulted statistically higher if compared to non-anemic controls (p = 0.003). Considering the most common cause of anemia, nutritional deficiency, chronic renal disease and anemia of chronic disease were found respectively in 36, 15 and 25 % of cases. Unexplained anemia was diagnosed in 24 % of patients, according to the literature. Anemia was independently associated with increased length of hospital stay. Our study confirmed a high prevalence of anemia in elderly patients, and its association with a higher number of comorbidities and a longer stay. A correct clinical approach to anemia in elderly hospitalized patients is essential, considering its negative impact on patients' quality of life, and its social burden in term of healthcare needs and costs.