According to different studies, anemia occurs in 8—33% of patients with chronic obstructive pulmonary disease (COPD). The paper describes the most important various causes of anemia in COPD, such as systemic inflammation and endocrine disorders, the use of some medications (theophylline, angiotensin-converting enzyme inhibitors), frequent COPD exacerbations, and long-term oxygen therapy. Lower hemoglobin levels in COPD patients are accompanied by increased shortness of breath, reduced exercise tolerance, and lower quality of life. Furthermore, some investigations have shown that anemia is an independent predictor of death in patients with COPD. In spite of the fact that anemia may be successfully in these patients, the evidence suggesting the importance of its impact on the prognosis of COPD is limited.