The purpose of the retrospective study in cancer patients in Poland was to analyze the frequency of anemia and methods of its treatment. An attempt was also made to evaluate the hemoglobin (Hb) levels in relation to patient's performance status (PS) prior to and after anticancer treatment. A total of 999 patients (pts) were enrolled, who were followed for up to six chemotherapy cycles or six evaluation points within a 6-month period. The incidence of anemia at the time of enrollment into the study equaled 31%, and was observed mainly among gynecologic and colorectal cancer pts. After anticancer treatment, anemia was reported in 54% of patients, mainly in gynecologic and lung cancer pts. As many as 71% of patients were anemic at some point of time during the survey, which was most often documented among gynecologic, lung and testicular cancer patients. At the 5th visit more than 50% of patients were anemic. The difference between the mean Hb level at 1st and 6th visit was 1.04 g/dL. However, anemia was treated in only 32% of patients (red blood cell transfusions, 61%; iron supplementation, 33%; while erythropoietic, stimulating proteins in just 6%). Worse PS was observed in anemic pts with lung as well as with head and neck cancer. In Poland the occurrence of anemia in cancer patients is as high as 70%. Anemia in this group of patients is underestimated and undertreated. This calls for more attention of physicians providing medical care to cancer patients.