Chemotherapy-associated neutropenia is often dose-limiting and may compromise treatment efficacy. Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage-colony-stimulating factor (GM-CSF) are increasingly used to prevent febrile neutropenia (FN) or to increase dose-density. This review discusses recent changes in treatment guidelines for chemotherapy-associated neutropenia. Primary prophylactic use of CSFs is now recommended as a treatment option at an overall risk of FN of 20%, not taking into account cost-effectiveness. To estimate the risk of FN, patient-, disease-, and treatment-related factors predicting an adverse outcome of FN have been determined. Dose-dense chemotherapy has become feasible with the use of CSFs. However, clinical benefit has been shown only for specific chemotherapy regimens in breast cancer, small cell lung cancer (SCLC), and non-Hodgkin's lymphoma (NHL), for the latter particularly for patients above 60 years of age. Strategies are being developed to tailor the use of CSFs to patients with a high risk of adverse outcome of FN.