Anemia is common in patients with cancer and is a frequent complication of myelosuppressive chemotherapy. In this study, we investigated the incidence and severity of chemotherapy-induced anemia caused by the most common chemotherapy regimens, including the new generation of chemotherapeutic agents, used in the treatment of the major nonmyeloid malignancies in adults. Five hundred fifty-two patients with histologically proven carcinoma originating from breast (n = 165), lung (n = 128), colon (n = 75), ovary (n = 84), and malignant lymphoma (n = 100) were included in this study. Hemoglobin levels for each patient were measured with an automatic counter during both pretreatment and before each chemotherapy cycle during therapy. To document the incidence of anemia, the National Cancer Institute grading system was used. Before chemotherapy, 44% of patients with breast carcinoma had anemia. There was a 16% increase in the incidence of anemia after chemotherapy. Severe anemia was observed in less than 1% of patients. No difference was found in the incidence of anemia between the fluorouracil, doxorubicin, cyclophosphamide (FAC) and cyclophosphamide, methotrexate, fluorouracil (CMF) regimens used in the adjuvant setting. However, single-agent chemotherapy with newer generation caused more anemia when compared with the FAC regimen (p < 0.005). Chemotherapy resulted in a significant decrease in hemoglobin levels when compared with pretreatment values in patients with lung cancer (p < 0.001). During treatment, the increase in the incidence of grade II anemia was associated with a parallel decrease in the incidence of grade I anemia. The incidence of severe anemia did not exceed 15%. The incidence of anemia was equivalent in both patients with small-cell lung cancer and those with non-small-cell lung cancer treated with the etoposide and cisplatin (EP) combination. Seventy-one percent of patients with colon cancer had anemia before initiation of chemotherapy. No difference was observed in posttreatment hemoglobin values compared with pretreatment values. Patients treated with irinotecan and fluorouracil and leucovorin (FUFA) combination showed similar rates of anemia. Incidence of anemia in patients with ovarian cancer at admission was 68%. Chemotherapy resulted in a prominent increase in incidence of anemia, which increased to 91.5%. There was an increase in grade II anemia, which corresponded to the decrease in grade I anemia. Less than 10% of patients developed severe anemia. No difference in the incidence of anemia was observed in patients with ovarian cancer treated with either cisplatin and cyclophosphamide or cisplatin combination. Showing a high incidence of anemia (82%) at presentation, hemoglobin levels in patients with malignant lymphoma were unaltered with chemotherapy. Severe anemia occurred in less than 3% of patients. There was a higher incidence of anemia in patients with non-Hodgkin's lymphoma receiving the cyclophosphamide, epirubicin, vincristine, prednisone (CEOP) regimen in contrast to patients with Hodgkin's lymphoma treated with the doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) combination. There was a prominent decline in the hemoglobin levels with cisplatin-based combinations in contrast to combinations including noncisplatin agents (p < 0.001). In this study, we have observed equivalent rates of treatment-related anemia when compared with previous data in patients with specific tumor types. The incidence of pretreatment anemia was high in various malignancies. The mechanisms underlying the propensity for a higher risk of pretreatment anemia in patients with malignant disorders and its influence on the outcome has to be elucidated by further population-based and molecular studies.